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Comparing Performance and Power Use For Vista vs. Windows 7 WIth Clarksfield Chi

Posted by timothy on from the batteries-need-help dept.

crazipper writes "Back when Intel launched its Core i5/i7 'Lynnfield' CPUs, Tom's Hardware ran some tests in Windows 7 versus Vista to gauge the benefits of the core parking and ideal core optimizations, said to cut power consumption in the new OS. It turned out that Win7 shifted the Nehalem-based CPUs in and out of Turbo Boost mode faster, resulting in higher power draw under load, while idle power was a slight bit lower. The mobile version of the architecture was claimed (at the time) to show a greater improvement in moving to Win7. Today there's a follow-up with the flagship Clarksfield processor that shows the same aggressive P-state promotion policies giving Win7 a significant performance advantage with Core i7 Mobile. However, power consumption is higher as well."

20 of 119 comments (clear)

  1. But what about ECC? by Timothy+Brownawell · · Score: 3, Insightful

    Given the recent google study and the Folding@Home NVIDIA study, why would you want to run an i5/i7 system (which don't permit ECC)?

  2. On what desktop system do you use ECC? by Sycraft-fu · · Score: 3, Insightful

    I haven't seen a desktop in a long time that had ECC RAM, or even support for it. In the Core 2 era of chips desktop use normal unbuffered DDR2 or DDR3 DIMMs. For ECC stuff on workstations/servers you use FBDIMMs which are way more expensive.

    Same shit with the i7. If you want i7 class hardware with ECC it is called the Xeon 5500. Running on a 5520 chipset, it supports ECC RAM, and lots of it (144GB is the most I've seen thus far).

    That's all workstation class stuff. Desktop stuff is not ECC because it is cheaper.

    1. Re:On what desktop system do you use ECC? by PitaBred · · Score: 2, Insightful

      Sometimes good enough is just that. People are used to restarting their computers and getting random blue screens. If a restart fixes it, they generally don't care. And that's fine by me. I don't use my machine for super-high precision work where a few bits flipped will cause massively different results. Nor do 99% of people. Why pay the extra 10% more when less than 1% actually might have a use for it?

      --
      My blog. Good stuff (when I remember to update it). Read it.
    2. Re:On what desktop system do you use ECC? by Timothy+Brownawell · · Score: 2, Insightful

      Sometimes good enough is just that. People are used to restarting their computers and getting random blue screens. If a restart fixes it, they generally don't care. And that's fine by me.

      I see it more as a problem that needs to be fixed, because even if most people use their computer for mostly entertainment they still use it for actual productive stuff at least occasionally.

      I don't use my machine for super-high precision work where a few bits flipped will cause massively different results. Nor do 99% of people. Why pay the extra 10% more when less than 1% actually might have a use for it?

      Because that "10% more" is going to be maybe $20 if you have unusually large amounts of RAM, and more like $5 for a $500 BudgetBox system that only has 2GB? That's probably worth it even for gaming (I'd imagine a bluescreen in the middle of an important raid or something could be rather annoying), let alone using TurboTax or doing office stuff for your small business (I seem to recall hearing that this includes a double-digit percent of the workforce?) or doing your homework at the last minute (I'm pretty sure almost all college kids do this).

  3. Isn't this what we want? by Korin43 · · Score: 5, Insightful

    Isn't this what we want? I mean, it's higher power under load because it switches to "fast mode" faster. Isn't that good? Yes it uses more power, but if the goal was to use as little power as possible, we'd just lock the processor in "slow mode".

    1. Re:Isn't this what we want? by JesseMcDonald · · Score: 2, Insightful

      ... if the goal was to use as little power as possible, we'd just lock the processor in "slow mode".

      Not necessarily. You also have to consider that higher performance settings may allow the processor to complete its task(s) and return to a minimal-power idle configuration more quickly, for an overall improvement in average power consumption. It all depends on the power/performance ratios for each performance level and the amount of overhead involved in switching between them. Plus, of course, a bit of clairvoyance in accurately predicting future requirements.

      --
      "The state is that great fiction by which everyone tries to live at the expense of everyone else." - Bastiat
    2. Re:Isn't this what we want? by SpelledBackwards · · Score: 3, Insightful

      Exactly. People seem to forget that power drain and energy consumption are not the same thing - power consumption is in energy consumed per some amount of time. For a completely unrelated example: If you run a 30 W load over 1 second, it will use 30 joules of energy (because a 1 W power draw means it consumes 1 J per second). But if you run a 500 W load over 1/100 sec, you'll only use 5 J of energy. Batteries store energy, not power, so what is likely to be more important for mobile platforms is which one used the least amount of energy over the time span of the test, not comparing peak power or power in short bursts of activity. That is, if you're concerned about battery life. Peak power might play a bigger role in talking about current load and CPU/battery temperature issues.

    3. Re:Isn't this what we want? by izomiac · · Score: 2, Insightful

      Not really. A CPU running at half speed uses something like 70% of the power that it does at full speed. So it's better to run at full speed for a short time, then go into power saving mode than to run at slow speed for a long time. This has been called "race to idle", and reminds me of the de facto motto of my old military school, "hurry up so we can wait".

      That said, Tom's Hardware did make a pretty big blunder on SSDs and battery life before, even having the gall to start that article with "Could Tom’s Hardware be Wrong? No, our results are definitely correct.". I haven't RTFA, but I'd be quite hesitant to take their word on anything to do with power consumption without carefully examining the methodology of their tests.

    4. Re:Isn't this what we want? by tlhIngan · · Score: 2, Insightful

      Not really. A CPU running at half speed uses something like 70% of the power that it does at full speed. So it's better to run at full speed for a short time, then go into power saving mode than to run at slow speed for a long time. This has been called "race to idle", and reminds me of the de facto motto of my old military school, "hurry up so we can wait".

      Actually, that's probably only true if you keep the voltage constant. If you can reduce the voltage to the CPU as you reduce the frequency ("DVFS" - Dynamic Voltage and Frequency Scaling), the power consumption at lower speeds is far lower than running the CPU twice as long. Power consumption varies by the square of the voltage.

      This is not a new technique - and is the core of many technologies like SpeedStep and the like. A frequency agile CPU is handy. But a frequency and voltage agile CPU is very handy. However, this complicates the power management software considerably - do you crank the speed up (and power consumption) to wait, or can you run it at a reduced rate and save power? An idling CPU consumes less power (especially if you can "slow-idle" it - reduce clock dramatically AND voltage - I remember an old embedded PowerPC that was so frequency agile, you could go from 200MHz operational to 33MHz when you entered the idle loop, and back to 200MHz when you left). But it's tricky since it takes time to do a speed/voltage switch and power.

      Activities where the CPU being as slow as possible would be media playback (where you want the frame to be ready just before it's needed, so you can stay in the busy-low-voltage-low-frequency range and not switch, which will save more power than cranking the CPU up, decode the frame, then crank it down and idle). But if you're doing something interactive, say, rendering a web page, it's more optimal to crank the CPU up, render the page, then crank the CPU back down and idle. A user is waiting for the output, and finishing their work fast may result in being able to stay in a low power state longer, or finish their work faster so the whole laptop can be put to sleep. The problem is, at the scheduler level, it's hard to tell what workload it is.

  4. Re:MacBook Pro by Shados · · Score: 2, Insightful

    Notebooks have done this for years (my girlfriend's 2-3 years old windows lap-top has that). Im guessing this is just Intel's flavor of it. Unless there's something fancier about Apple or Intel's offering like being able to do it on the fly without any settings to toggle or bios interaction, like CPU stepping.

  5. Re:Good grief by Seth+Kriticos · · Score: 2, Insightful

    They obviously don't. Some cohesive naming might give you at least an indication on what you are dealing with.

    My favorite is the nVidia one: GF 6xxx -> GF 7xxx -> GF 8xxx -> GF 9xxx -> GT 2xx .. WTF?

    Now don't ask me why. I think it's stupid.

  6. Powering the chipset and backlight by tepples · · Score: 5, Insightful

    while under battery power the CPU will do everything it can to conserve power under the same software load conditions.

    In many notebooks, the CPU does not dominate battery consumption; the northbridge, southbridge, and LCD backlight draw a significant fraction of the power. So when CPU usage hits 90%, clocking it up to full power is warranted because it gets the work done faster, meaning that the chipset and LCD don't run as long while the user is waiting for the CPU to finish.

  7. Situations like this are why I run Intel chips by dave562 · · Score: 3, Insightful

    I primarily use Microsoft software (I know, get out the pitchforks) and over the years I have occasionally run AMD chips after being overcome by various AMD biased friends of mine. I've never been able to put my finger on it, but Windows simply doesn't run as well on AMD chips as it does on Intel chips. I always end up switching back to Intel. This article is just an example of why. Intel and Microsoft are in bed with each other, and Microsoft will always be putting out the code to take full advantage of the Intel chips. It wouldn't surprise me if Intel gives Microsoft the heads up on new features far in advance. It wouldn't surprise me if Microsoft works with Intel and encourages them to develop certain features in their processors that will help the Microsoft code base execute faster.

    1. Re:Situations like this are why I run Intel chips by dave562 · · Score: 3, Insightful

      What is flame bait about my post? Intel and Microsoft work closely together to optimize the user experience. Must be AMD fans with mod points today.

    2. Re:Situations like this are why I run Intel chips by Anonymous Coward · · Score: 5, Insightful

      Riiight.

      Certainly Intel and Microsoft work closely together, they have many reasons to. But I've used many AMD and Intel systems, and honestly they're pretty interchangeable in terms of user experience.

      Claims that Windows only runs right with Intel is at best, inaccurate. Are you forgetting things like the adoption of the AMD64 architecture as The Way Forward for Microsoft in terms of 64bit support, over Intel's offerings..

    3. Re:Situations like this are why I run Intel chips by Com2Kid · · Score: 2, Insightful

      My Win7 quad core AMD system that boots in under 10 seconds, is rock solid stable, and runs every game I throw at it blindingly fast would care to disagree with you. :)

      Link to my PC build out. I was going more for cosmetics (30 lbs of brushed aluminum, I don't much like the blue LEDs though, I am burnt out on blue LEDs) than for power, I have friends who consider a 10 second boot with Win7 to be slow. Not that I boot very often, more likely I am coming out of Hibernate which I can do in ~3-5 seconds, which is pretty good timing for 8GB of RAM.

      I've never been able to put my finger on it, but Windows simply doesn't run as well on AMD chips as it does on Intel chips. I always end up switching back to Intel.

      Intel makes very stable chipsets. If you tried AMD during the days that they were relying on Via chipsets (or used some of AMD's early chipsets) I can see how you could easily get this impression. Intel is good at putting together barebones kits and working with OEMs to put out stable systems.

      Also don't skimp on the mobo, get a good middle of the range one, and read reviews on it. AMD's platforms have always offered a lot of diversity, which can be both a strength and a weakness; depending on how educated the system builder is about the relative merits (including stability) of those choices.

      AMD is often seen as a cost cutting measure (and their CPUs are very financially efficient) but a lot of people, both OEMs at individuals, take cost cutting a bit too far and once they go with AMD they also skimp on the power supply, motherboard, and even RAM.

      Indeed, an AMD system with a very well performing CPU that has been hooked up to a crash prone motherboard running no-name RAM all powered by a flaky PSU, can indeed give one a very negative impression of AMD as a whole. :)

      AMD MoBos are typically cheaper than comparable quality Intel MoBos, so you can save some money there, but don't be cheap with any other parts of the system. You will still save a good chunk of change (how much depends on which company has done price drops most recently) and you will get a stable, reliable, very well performing system.

      --
      Need help treating your acne? Come here!
  8. still worth the upgrade by sabhead · · Score: 2, Insightful

    its still worth it to upgrade to windows 7. vista is just too terribly slow. i think a lot of people are holding back from purchasing computers because no one wants to be stuck with vista.

  9. Re:Windows Update by Canberra+Bob · · Score: 4, Insightful

    I am no Linux fanboi by any stretch of the imagination however I have to agree with the parent. In my personal experience, regardless of hardware configuration, even a brand spanking new build will slow to a dead crawl (for all intents and purposes unuseable) when performing updates.

  10. Re:MacBook Pro by PopeRatzo · · Score: 3, Insightful

    So the worst thing you can say about Win7 is that it performs better but uses slightly more power in some rigs?

    Desperation sets in...

    --
    You are welcome on my lawn.
  11. Test is pointless by Trerro · · Score: 1, Insightful

    Windows 7 is an upgrade to Vista, and it performs better. This isn't news.

    The problem is that Vista is a HUGE downgrade from XP, and so far everything I've read says that 7 is simply less of an XP downgrade than Vista was. I couldn't care less if it's prettier - it either needs to have some major functionality that XP doesn't (and it doesn't), or it needs to offer a serious performance boost over XP (and it appears to do the opposite.)