Intel's Haswell Moves Voltage Regulator On-Die

MojoKid writes "For the past decade, AMD and Intel have been racing each other to incorporate more components into the CPU die. Memory controllers, integrated GPUs, northbridges, and southbridges have all moved closer to a single package, known as SoCs (system-on-a-chip). Now, with Haswell, Intel is set to integrate another important piece of circuitry. When it launches next month, Haswell will be the first x86 CPU to include an on-die voltage regulator module, or VRM. Haswell incorporates a refined VRM on-die that allows for multiple voltage rails and controls voltage for the CPU, on-die GPU, system I/O, integrated memory controller, as well as several other functions. Intel refers to this as a FIVR (Fully Integrated Voltage Regulator), and it apparently eliminates voltage ripple and is significantly more efficient than your traditional motherboard VRM. Added bonus? It's 1/50th the size." Update: 05/14 01:22 GMT by U L : Reader AdamHaun comments: "They already have a test chip that they used to power a ~90W Xeon E7330 for four hours while it ran Linpack. ... Voltage ripple is less than 2mV. Peak efficiency per cell looks like ~76% at 8A. They claim hitting 82% would be easy..." and links to a presentation on the integrated VRM (PDF).

Comments

excited

[Anonymous Coward]

come guys, comment, so I know how excited I should be

Re:excited

[Anonymous Coward]

The 1.2V regulator will actually produce 1.199988484939848 volts !

Re:excited

[Lotana]

All good guys, he is gone. We can go back to our regular insightful, interesting and funny posts again.

sinking heat?

[p51d007]

with the on die regulator, won't that area of the chip be a tad warmer than the rest of the chip, or will the heat be a moot point?

Re:sinking heat?

[dotgain]

Heat hopefully won't be an issue. Let's hope heat output scales at least somewhat with component size that is 98% smaller.

And why would it do that? A given voltage drop multiplied by the current through it equates to a certain wattage of heat dissipation, regardless of the size of the package.

Re:sinking heat?

[adolf]

Your broad generalization is only if it is a linear regulator. Switch-mode regulators change the game. TFA doesn't seem to indicate which it is.

Re:sinking heat?

[__aaltlg1547]

It's a switch-mode (Buck) regulator. You can tell from the efficiency curve and the fact that it requires an inductor. It is more efficient than a linear regulator and less efficient than a good external Buck regulator. However, being on-chip it will regulate the voltage better because there won't be significant I*R drop between the regulator output and the load. And as they mention, the cooling fan will be right on top of it, so it is more effectively cooled than an external regulator typically is.

Re:sinking heat?

[viperidaenz]

The voltage regulation issue can easily be solved by having a feedback connection from the die to the external VRM.
There are only two benefits I can see:
1) Higher voltage in to the chip means lower current, which saves power. You I*R formula is slightly wrong, its actually I^2 * R, double the current means 4x the power loss.
2) Lower system cost. the more crap that gets stuffed on the die/in the chip, the less is required on the board. That means fewer components, smaller board area and quicker assembly.
There are of course other benefits that only benefit Intel
a) Fewer external components means they can charge more for their chip without effecting system cost.
b) smaller system = happier customer = will pay more
c) If it does actually result in lower power, then you get more performance or more battery life = customer will pay more

Re:sinking heat?

[viperidaenz]

Watts is used to measure heat.

http://en.wikipedia.org/wiki/Thermal_resistance

The unit is "degrees per watt". As in "5C/W" = "this heat sink will rise by 5 degrees dissipating 1 watt"

Heat

[girlintraining]

Intel refers to this as a FIVR (Fully Integrated Voltage Regulator), and it apparently eliminates voltage ripple and is significantly more efficient than your traditional motherboard VRM. Added bonus? It's 1/50th the size."

I have yet to come across a voltage regulator that doesn't run hot. Typically, it's one of the hottest components in an electrical circuit. And we're integrated this into a slab of silicon already well-known for getting so hot it can catch fire?

Can someone please tell me why this is a good idea, because all of my experience in electrical engineering says that when things heat up, they become more unstable and prone to failure, and the one thing you do not want going critical is your voltage regulator. If that goes, the whole computer catches fire.

Re:Heat

[Anonymous Coward]

Most likely, because it's integrated into the CPU itself, the voltage regulator can be made more efficiently and thus save power and heat etc. Discrete parts have their limitations, and doing it on-die might just mitigate that.

Re:Heat

[Anonymous Coward]

You're going to run into that heat anyway, whether it's on the motherboard in general or on the CPU. You can't win. But at least it's better to have heat build-up near a heat-sink, so for high-power conditions it might actually be better to put it on the CPU. I'm also an electrical engineer, but thermals are really a mechanical engineer's realm, so I can't run numbers for you.

Re:Heat

[rrhal]

Being 1/50th the size it will be welcome on mobile devices. Not sure that its a good thing for your gaming desktop.

Re:Heat

[fuzzyfuzzyfungus]

My suspicion(if only for die-space reasons, it isn't purely cosmetic that contemporary VRMs occupy a substantial amount of board space) is that is this a 'marketecture' summary of Intel moving some additional voltage adjustment and power gating functions on die, to support dynamic adjustment of power to the greater number of components(multiple CPU cores, possibly independently clocked, GPU, RAM controller, PCIe root, etc.); but we'll still see a bunch of chunky power silicon under serious heatsinks clustered around the CPU socket.

Given that much of the contemporary power savings are achieved by superior idling, rather than absolute gains in maximum power draw, Intel is either going to have to keep moving power regulation on die, or start dedicating even more pins to tiny voltages at nontrivial currents, with the associated resistive losses; but that won't necessarily change the fact that the circuitry that brings the 12v rail down to what the CPU wants is a pretty big chunk of board.

Re:Heat

[Virtucon]

Well even at 10W I'm wondering how they'll address the heat.
With the density of circuits in the adjacent silicon I would wonder how they're providing enough isolation to prevent it from becoming a very small brick.

Re:Heat

[citizenr]

I'm not an EE so I won't pretend to fully understand this particular case but I like it when tech companies reach a bit and try something hard. This may or may not be a good idea but I'm still excited about it.

Thats what she said.

Re:Heat

[Anonymous Coward]

Considering that they've already started shipping an actual product, perhaps you should switch modes--from skeptic to sleuth. Start from the proposition that (a) it's possible or (b) they're leaving something out of the marketing jargon. There are a million ways they could do it wrong, and likely only a few ways to do it right. If you start from the proposition that Intel is shipping a working product, then it should be much easier to figure out.

Re:Heat

[girlintraining]

My suspicion(if only for die-space reasons, it isn't purely cosmetic that contemporary VRMs occupy a substantial amount of board space) is that is this a 'marketecture' summary of Intel moving some additional voltage adjustment and power gating functions on die, to support dynamic adjustment of power to the greater number of components(multiple CPU cores, possibly independently clocked, GPU, RAM controller, PCIe root, etc.); but we'll still see a bunch of chunky power silicon under serious heatsinks clustered around the CPU socket.

That's the only plausible thing I could come up with as well. The control logic could go into the CPU, but I don't see how pulling 12V down to fractions of a volt is going to happen on the die itself without it burning a hole through the board; heatsink or not, you can't escape Ohm's Law.

Re:Heat

[Kjella]

Can someone please tell me why this is a good idea

The long story is here (PDF). Motherboard will still do the heavy lifting from 12V to 2.4V, but the integrated VRM will distribute it. Advantage is extremely clean, fine-grained, low-latency and flexible power supply to deliver exactly as much power to where it's needed and probably - this is just speculation on my part - allowing the CPU to work on a wider range of voltages since there's less noise and ripple so you don't need the same tolerance limits. It sounds perfect for smart phones, tablets and laptops that are primarily battery-limited, nice to have for average machines but potentially an issue for overclockers. All you need is cooling though, it shouldn't limit overclocking if you can keep the temp down.

Re:Heat

[girlintraining]

you can't escape Ohm's Law.

Actually you can. It's called a switching power supply.

In other news, a Nobel Prize in Physics was awarded to Anonymous Coward of Slashdot today, after discovering that the laws of physics do not apply to switching power supplies... His next research proposal is on solving the energy crisis by designing keyboards to detect when someone is angry and then increasing the key resistance by piezoelectric effect to generate energy. While it would generate only marginal amounts of power when used by 99.975% of the population, it was recently discovered that the remainder are actually Linux and Apple fanboys who, if fed a regular diet of dismissives via their computer screen, will so furiously hit the keyboards that power for entire cities is easily achievable.

Re:Heat

[__aaltlg1547]

Being 1/50th the size it will be welcome on mobile devices. Not sure that its a good thing for your gaming desktop.

That 84 watts is going to rip through your mobile device's battery pretty damn fast.

Re:Heat

[ebno-10db]

Being 1/50th the size it will be welcome on mobile devices.

It's not clear how they measure "1/50th the size". I could be wrong but it sounds like marketing hype. With a switching regulator the inductors and capacitors generally take up much more real estate than the chip. If they have some magic way to reduce the inductor and capacitor sizes it isn't mentioned in the article (and that would be a much bigger deal than just putting the regulator on the die).

Re:Heat

[petermgreen]

You can reduce the inductor and capacitor sizes a lot by increasing the switching frequency. Of course doing so will likely increase your switching losses but it may still be worth it if it lets you put the regulator closer to the load. Especially given the ever lower voltages that modern chips are running at.

Re:Heat

[ebno-10db]

You can reduce the inductor and capacitor sizes a lot by increasing the switching frequency.

But you can do that w/ an external regulator too. Apparently the secret is on-chip inductors. Now that's impressive. I'm surprised that some of the "analog" companies making switchers didn't come up with that first. I know Intel has good fab tech, but this seems more like the sort of funky thing analog guys would come up with first.

http://www.psma.com/sites/default/files/uploads/tech-forums-nanotechnology/resources/400a-fully-integrated-silicon-voltage-regulator.pdf

Re:Heat

[Anonymous Coward]

Actually, no real device is ohmic at all. Even a resistor will heat up with increasing current causing an increased resistance that is non-linear. For us EEs, ohmic devices are our massless pullies and frictionless inclines.

Re:Heat

[Omega Hacker]

Ohm's law is completely irrelevant to this situation *in the form you describe*. "Burning a hole through the board" would be possible and a simple function of Ohm's law only if they were using a linear regulator to generate the Vcore. But VRM's have been switching DC/DC converters since the 486 days. They achieve a voltage conversion by switching the incoming voltage on and off *very fast*, which results in an output voltage that's a function of the input voltage and the duty cycle of the on/off switching. An inductor (current-smoothing) and capacitor (voltage smoothing) give a nice clean DC voltage.

The differences between on-motherboard VRMs and this new in-package (it's technically a separate chip...) are significant. First off, physically moving it closer means that you're not sending 100+ Amps of current over the 3-4 centimeters of generally very thin copper traces on the PCB, they're sent millimeters through die-bond wires, or even through a solid substrate (no idea what Intel does at that level). There's your Ohm's law coming into play at that level, but the power losses there are relatively minimal since you're talking maybe a few tenths of an ohm. Die-bond wires are going to drop that to 10's of milli-ohms probably, so nothing major but still a positive effect.

The main reason this will generate a lot less heat is because of the *frequency* of the switching. Because this on-board VRM is so much smaller, it can switch the input faster (shorter wires, less parasitic capacitance, less ringing, etc.). This in turn means smaller value components required, e.g. the switch from the monster inductors seen on the motherboard (at maybe 1-2MHz switching) in the slide to the tiny chip-scale inductors on the FIVR (at 10's or 100's of MHz). The end result of all of this is that switching losses get significantly smaller. It's those losses that create heat local to the regulator. If they can for example go from an 80% efficient VRM to an 90% efficient FIVR for a 100W CPU load, they reduce the switching losses from 25W to 11.1W.

Re:Heat

[girlintraining]

Actually, no real device is ohmic at all. Even a resistor will heat up with increasing current causing an increased resistance that is non-linear. For us EEs, ohmic devices are our massless pullies and frictionless inclines.

I'm not a certified EE, but I have built electronic circuits. I know there's a lot of ways to 'cheat' on paper; switching power supplies don't get rid of ohm's law though, they're simply more efficient. Ohm's law is about the relationship between resistance, voltage, and current. Those relationships are derived from the physics about electron exchange between different materials. Now yes, capacitors and inductors both run 90 degrees out of phase between voltage and current so it can appear to be violating ohm's law, but if you apply a correction factor you'll see it's pretty close to parity. When you get down to really small discrete components, like a transitor for example, measurement inaccuracy and time domains will really start to screw with you, but ohm's law still holds even down to that scale.

Ohm's law is the reason for these changes Intel is making: An attempt to remove parasitics from the circuits, which all boil down to resistance; Whether it's phase-shifted forward because of capacitors, or backwards because of inductors, or because of components that create those effects, doesn't really matter.

Now you're right, a purely ohmic device doesn't exist. Even resistors can generate small amounts of phase shift. But that doesn't make them "massless pullies" or "frictionless inclines". Ohm's law is still useful for the same reason the OSI 7 layer model is still useful, despite no network yet having been designed that perfectly adheres to it...

Re:Heat

[viperidaenz]

If you core requires 1V and 90 watts you need to transfer 90A through your PCB traces, up in to the chip, across the bond wires (if there are any) and on to the die.
If your die has a regulator on board and accepts 12V instead, and is 80% efficient you only need to transfer 9.4A. You've just lowered your resistive losses by about 100x. If the connection between the external VRM and die is 0.001ohms, at 90A you waste 8.1W. at 9.4A you waste 0.088W.

Re:Heat

[fluffy99]

. This in turn means smaller value components required, e.g. the switch from the monster inductors seen on the motherboard (at maybe 1-2MHz switching) in the slide to the tiny chip-scale inductors on the FIVR (at 10's or 100's of MHz).

From the linked pdf - Programmable switching frequency 30MHz to 140MHz

Re:Heat

[allanw]

So what stops someone from taking the switching frequency really high, like into the hundreds of megahertz? In switching regulators, there is both conduction loss and switching loss. Conduction loss occurs from resistance in the power supply path, including switch resistance. It can be reduced by increasing the switching frequency. However, this increases the switching loss -- you have to switch the power FET gate capacitance more often. The most efficient system is achieved when conduction loss is balanced with switching loss. It is a complex engineering problem. By making a tiny package integrated solution, the inefficiencies of switching can be reduced so the frequency can go up. This cannot be easily done with a traditional discrete-based system like on current motherboards.

Re:Heat

[dgatwood]

Intel might be the first to do it on a CPU die, but they're not the first to do on-silicon inductors by any stretch. Switching regulators with inductors on silicon have been commercially available for several years now. The R-78 and MIC33030, for example, are drop-in replacements for linear regulators, with all components on die.

The real question in my mind is why anyone still uses linear regulators for anything, but I digress.

Re:Heat

[SuricouRaven]

That R-78E3.3-0.5 looks useful... the raspberry pi uses a rather inefficient linear regulator to take the 5v input down to 3.3v. An NCP1117. Can't just replace it with an R-78, as the minimum input voltage is 6V, but if you're running it off of something higher... yes. This component may be of use to me.

Re:Heat

[Anonymous Coward]

Sorry, but I design quite a lot of switch mode regulators for my own hardware design, and there are several concerns here:
- the efficiency of 76% they claim is abysmally low, my regulators are never below 80% in their operating range, and often above 90%, with peaks in the 96-97% range.
- switch mode regulators need an inductor, and inductors need ferrite or iron cores, which is not going to happen on a silicon die. External inductors are much better
but low loss inductors for large currents are large, for fundamental physical reasons.
- the fastest acheivable switching frequency is in the low tens of MHz, and this is with considerable losses. Lowering the frequency decreases the losses which happen while the swictch(es) change state, which are dominating at higher swictching frequency. At lower switching frequencies, losses are dominated by I2R
in chokes and traces.
- increasing switching frequency allows to increase loop bandwidth and transient response, but another way to improve transient response is to increase output capacitance, which is relatively cheap at low voltage and is best attained by a parallel combination of ceramic capacitors (class II dielectrics like X5R/X7R, never use class III like Z5U or Y5V, they have horrible temperature and voltage dependent characteristics) for high frequency filtering and low ESR tantalum (like
AVX TPS, designed for this task) for absorbing transients while the regulator adapts within the limits of the loop bandwitdh.
- loop bandwidth can never be much above one tenth of the switching frequency, to avoid excessive phase shifting due to the sampling that makes the loop unstable
- an efficient way of minimizing ripples is to have several regulators in parallel with the same clock phase shifted. I've got exceptionnally low ripple in this case
(could not measure it with a good scope, not with a voltmeter whose bandwidth included the switching frequency).
- for the large currents, the regulator will be dierctly connected to a ground plane and to an output voltage plane, voltage drops on plane should be low enough
if you put enough vias to the component (BGA/LGA), and you can always sense the voltage back from the largest consumer.

Re:Heat

[serviscope_minor]

Most likely, because it's integrated into the CPU itself, the voltage regulator can be made more efficiently and thus save power and heat etc. Discrete parts have their limitations, and doing it on-die might just mitigate that.

I'm not sure that follows. For transistors doing computation, the efficiency saving is by reducing the amount of current that they have to switch. In this case, all they're really doing is building a very large MOSFET onto the die itself along with a bit of other gubbins.

Also, the efficiency figures they claim aren't very high compared to other buck regulators. For example, a quality PSU exceeds the efficiency figures they claim.

In fact, using a really tiny process size for power components is no advantage since you start to suffer on things like the short channel effect. As such the process won't provide any advantage since they'd have to fab the power device to be much larger than the process size anyway.

All in all though, they're moving 10W or so from an external power device to an internal one. It's not going to be a huge change either way.

Re:Heat

[serviscope_minor]

But you can do that w/ an external regulator too. Apparently the secret is on-chip inductors. Now that's impressive. I'm surprised that some of the "analog" companies making switchers didn't come up with that first. I know Intel has good fab tech, but this seems more like the sort of funky thing analog guys would come up with first.

They did.

I did a semiconductor course on analog CMOS as an undergrad over 10 years ago. It's interesting because the CMOS processes are typically adapted for digital electronics, and can't give things like BJTs without modification. The radio (phone, wifi, bluetooth) companies want to make analog circuits as cheaply as possible, which means using older gen CMOS to do analog.

Firstly you put down a bunch of metal in a spiral shape to make the inductor. That bit is easy.

Getting the Q up is interesting, because especially on a bulk silicon process there is a lot of stray capacitance.

Due to some weirdness of surface chemistry which is beyond me you can etch preferentially along certain cleavage planes, which means with care you can actually dig under the spiral using careful placement of SiO2 and bare silicon patches.

I doubt intel do that though since there's no need to get such high Q outside of radio receivers.

Can some practicing semiconductor engineer chip in?

Re:Heat

[thegarbz]

What an absurd statement. Just because a device has non-linear characteristics doesn't mean that V=IR is any less useful.

LEDs are non-linear yet we use V=IR as way to determine the required compliance of a current source, or what resistor you need if you go down the easy voltage source route. Or an example closer to home, the MOSFET may have a non-linear and time changing characteristic while turning on, but the regulator's power efficiency is none the less determined by the I^2R losses. That doesn't change just because R changes with time and voltage.

The only time it becomes useless is when power is radiated out of the circuit as in antenna theory.

Re:Heat

[fnj]

Well even at 10W I'm wondering how they'll address the heat.

Are you serious? Essentially all of the power going into the CPU is coming out of it as heat already. That's 35-100+ watts of heat already being dissipated. And you're worried about another 10 watts?

Re:Heat

[nerdbert]

I do SoCs with integrated regulators now.

Their inductors are on-chip using extra thick metal levels. But "extra thick" levels on sub-20nm chips are still pretty damn thin, meaning high r/square, so the Q they can get out of the inductors is pretty low, especially since the configuration they use (linear coupling rather spiral) will also limit their available Q. That's what's driving their efficiencies down from what you're used to in discrete buck regulators.

The big advantage of integrating this is that you don't get the all the nasties of the pads. You usually get the power routed to the corner pins on an SoC and a big chip can easily generate 20+ nH and 1 pF on the pins of a wirebond SoC, and even a flip-chip will still see more than 10 nH typically. That's a problem when trying to deal with power transients, so the on-chip regulator really helps get the ripple down since it can sense/adapt to the voltage at the pin.

Personally, the big eye-opener to me was doing 400A of DC power on chip. Even at sub-1V the electromigration issues they have must be killer.

Re:Heat

[nerdbert]

Discrete buck regulators lose efficiency above roughly 1 MHz due to the parasitics associated with the pass devices and pads. You'll see fully integrated solutions that run at 5 MHz or so if they're meant to supply other chips simply because the parasitics will generally limit the performance to around that frequency. Specialized systems (like the regulators to previous Intel CPUs) can run higher than 5 MHz, but in general the return isn't that good for increasing the frequency.

Putting the regulator on the same chip changes the ball game since the pad parasitics in particular are avoided. There you can run much, much higher in frequency and the Intel guys go up to 167 MHz/phase in their presentation.

Full presentation

[AdamHaun]

You can find the full slide set in PDF format here.

If I read this right, it really is a fully on-chip switching regulator, inductors and all. They already have a test chip that they used to power a ~90W Xeon E7330 for four hours while it ran Linpack. (Or a virus -- it says Linpack in the summary page.) Voltage ripple is less than 2mV. Peak efficiency per cell looks like ~76% at 8A. They claim hitting 82% would be easy, and there are "additional advancements that cannot be reported at this time" planned for the future.

The slides have bunch of other technical details about testability features, too, which is always neat to see.

Re:Full presentation

[girlintraining]

hey already have a test chip that they used to power a ~90W Xeon E7330 for four hours while it ran Linpack. (Or a virus -- it says Linpack in the summary page.)

Respectable viruses take issue with your comment that Linpack is anything like them. Viruses do useful work.

Re:Full presentation

[allanw]

An Intel CPU has a TDP of 90W+ running under 1V. That's 100A+ from the switching power supply. With resistive loss, and inefficiencies from multi-phasing the regulators, efficiency are worse than you say. The cost is also high -- having all of this integrated into the package saves on the platform cost.

Re:Full presentation

[allanw]

The term "virus" in this context means a power virus -- which is an artificial workload designed to draw as much power as possible from the chip. For example, normal CPU burn stress tests might only activate 90% of the chip's power consumption, but a specially designed power virus would be able to activate all of it. In some cases designing the thermal and power integrity solution to support the chip's full power consumption under a power virus needlessly adds extra costs to a product, because it will never see that workload in real life. It's a virus because a malicious person might be able to activate this mode and melt down your CPU, so typically they _do_ have to design the system to support it.

Re:Yawn

[wbr1]

Apparently your e-peen is already small enough to fit on die.

From a former power supply designer - Neat!

[jimmyswimmy]

That's some amazing work. The current state of the art in CPU power supply designs hasn't changed in 15 years. 12V in, low voltage out, and the output voltage has been moving lower and lower for years, with designs below 1 V. If you figure you had a few percent of tolerance in the early years when everything ran off 2.5V and that few percent remains constant, then at 1 V you have almost no room for slop. So there are a lot of output capacitors there, both those electrolytics (you always hear people complaining about them but they're CHEAP) and ceramics. The ceramics cost a fortune and you need a lot of them to get your tolerance down - the first half microsecond of a load step is entirely the ceramic capacitor's response, not the controller or anything else. Moving part of the VR onboard allows them to reduce the parasitics significantly and they can probably tolerate a little higher tolerance as a result, but moreover they can get rid of some of those ceramics in the whole system - ultimately many of those on the motherboard.

So this is taking a lot of cake out of company mouths. Analog, Intersil, IRF, ON, who else - manufacturers of controllers, MOSFETs. Inductors, ceramic and 'lytic vendors are all going to lose out a bit here. Potentially Intel can reduce the platform cost vs. AMD as well, which is interesting. There is still an onboard VR but it will be 12 - 2.4 V, wherever they think the sweet spot is for efficiency and size. And the first real change in this industry for a long time. Cool work.

Re:From a former power supply designer - Neat!

[ebno-10db]

http://www.psma.com/sites/default/files/uploads/tech-forums-nanotechnology/resources/400a-fully-integrated-silicon-voltage-regulator.pdf

Re:Rotten idea for performance

[Anonymous Coward]

You should contact Intel - I bet they didn't even consider this.

Re:Yawn

[Dachannien]

Seriously? And here I thought I was being clever. I bow to the master.

Re:I am totally impressed

[jimmyswimmy]

Not such a big breakthrough as you'd think. As you increase the switching frequency you can decrease the value of inductor and capacitors required. Last CPU supply I built - 10 years ago! - used 100 nH inductors at 300 kHz per phase. I skimmed the PSMA article but there was mention of MHz operating speeds, not at all unheard of these days, so the components ought to be much smaller. A 10 nH inductor and some hundreds of pF of capacitance seems very feasible without stretching the bounds of silicon technology at all.

No it's about ripple

[dutchwhizzman]

If you'd read at least the summary, the benefit would be less ripple. Because it takes time to get the feedback voltage to the external VRM, there would always be ripple if power demands would fluctuate fast enough. In a typical CPU on a typical load, you get a lot of power load changes, so you'd get a lot of ripple. Ripple means that ultra low power circuitry will be harder to implement and hit limits earlier, since it is more dependent on precise voltages.

Power saving wouldn't be relevant, if you are looking at the power loss in the circuit board traces to the CPU. The efficiency of the internal regulator is lower than that of external voltage regulators so it would probably consume even more power.

System cost would be higher. Other components on the main board still require regulated voltages, so no components would be saved there.

Re:No it's about ripple

[thegarbz]

System cost would be higher. Other components on the main board still require regulated voltages, so no components would be saved there.

This is actually something you're wrong about. A modern CPU require 3 distinct voltages separate from all other devices on the motherboard. The bus, northbridge, memory, and every other non-cpu component will run at different voltages. About half of the regulators that take up real-estate directly around the CPU serve only the CPU. These components could be saved.

Re:I am totally impressed

[InvalidError]

Nothing new about physics there. It has been known for decades that a piece of wire starts behaving like an inductor at high frequencies and parallel wires or planes behave like capacitors. Both notions have been in use for high-speed analog and RF ICs and PCBs for a long time. For capacitors, there is even a whole class called "Multi-Layer Chip Capacitor" which is basically an IC with several metallization layers connected at alternating ends.

This is simply the somewhat unexpected but logical application of well-known principles to an old problem: making PSUs smaller.

The real breakthrough here is a VRM solution capable of operating reasonably efficiently at 30+MHz with a multi-phase architecture that brings ripple frequency over 500MHz; within the realm of what can be filtered on-chip.

What are you all talking about?

[ckatko]

I looked through everyone's comments, hoping to see this important issue and everyone's too busy debating silly shit like heat. When is the end-effect of paradigm shifting ever the same as the issue a company portrays to the public? Did everyone think "Microsoft Open Technologies" was a true attempt at embracing open source software?

Let's look at what's actually going on:

• 1. Overclocking allows for people to buy cheaper processors that do the same thing as more expensive ones.

• 2. Increased voltage is required for overclocking.

• 3. Placing the voltage regulator on the CPU instead of the motherboard removes the control from the motherboard manufacturer and end user.

The end result?

• 4. Overclocking can only be achieved by "official overclocking CPUs" that cost much more.

Intel is working to take away the control people have over their processors. Whether this is the final step, or just a means to an even bigger end, we should be asking more questions.