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Is Rambus Destined to Return?
An anonymous reader pointed us to an article running over at Tom's that talks
about the world
of ram and criticizes the performance of DDR. The article goes
into DDR333, DDR400, and Rambus, and explains the issues at higher
clockspeeds.
Experience tells us that Rambus is faster.
Pocket books tell us that ddr is better.
Which will your wife let you decide on?
Given the bad performances of RDRAM due in large part to its insanely high latency, and Rambus' dubious business practices based mainly on trying to milk patents to leech on the entire memory industry's back, why on earth should anybody give then the opportunity to make a come-back ?
It seems to me that Rambus has offended so much of the industry that it even intel's continued (though lately lessening) support, or perhaps especially with intel's support it will fail to be implemented by the majority of m/b manufacturers.
Other avenues for gaining speed exist- like Nvidia's extra memory controller for the gpu in the xbox and higher end nForce chipset.
With the exception of the shady business practices of Rambus, I don't fully understand why Intel dropped RDRAM in the first place. In every benchmark that I saw circa 7-8 months ago, the huge amount of memory bandwidth present gave Intel one of it's only advantages over the corresponding AMD CPUs.
It couldn't have just been the prices either, because Intel obviously knows they're not going to win that race.
Anyone?
Palaces, barricades, threats, meet promises
Sorry...
Why is Grand Theft Auto a much more serious crime than Reckless Driving?
Seriously, ignoring pure performance considerations, RDRAM is garbage. It has to be put in pairs, and if those pairs aren't made by the same manufacturer, I've seen motherboards refuse to boot. Heat is a serious issue, and I've burned one finger too many on those heat spreaders. I've also seen an analog cable coming from the cdrom get stuck between the RIMM's and melt to the heat spreader. And price is still an issue, although it's improved quite a bit recently.
Expensive + Has to run in pairs + Runs very hot == Useless to me.
---- El diablo esta en mis pantalones! Mire, mire!
This can be a problem. You should be able to make back the money so you cover your costs. Unfortunately, you may have to have deep pockets to stay in the game for a long time.
"It is a greater offense to steal men's labor, than their clothes"
The fact is that most IC testers today support the lower-speed parallel connections. High-speed serial connections like Rambus and SERDES require very expensive mixed-signal testers with expensive and complicated load boards (the PCB between the tester itself and the chip). These high-speed serial I/Os on the memory ICs themselves are also generally much larger than on a DRAM, probably by a factor of 5. So, you don't get die savings, you don't get lower test costs, and most of all you don't have any processors whose front-side buses exploit this. Plus, you have very expensive target products in terms of motherboards to support the Rambus ram requiring tight trace routing and signal isolation, and their very limiting 28ohm max impedance (at least with the PC800 RDRAM), almost completely opposite in difficulty to DDR. So where's the advantage?
If you also figure that the memory controllers for Rambus are configured for dual-channel operation, it becomes much clearer that the advantage is not in the memory architecture itself but in the controllers. Suppose a server board manufacturer decides to support quad-channel PC2700 1GBx4. That's 10.8 GB/s of potential memory bandwith on sequential accesses! There's hope with chipsets like the Nvidia nForce420 dual-channel DDR, but the Athlon FSB is the limiting factor there. And let's not get into the infamous first-access latency issues which I hope they're finally addressing.
Rambus is also notorious for poor tech support. I worked for a major silicon vendor using their core, and they never responded to our requests for minimum PLL-to-Rambus core distances. It was abjectly ridiculous, but not surprising considering that regular SDR/DDR memory interfaces outnumbered Rambus designs 100:1. Have things changed? Considering what their legal bills have been lately and an erosion of their tech support, I doubt they can afford to improve it much.
on what systems you are working with? if you want a performance p4 system then obviously you use rambus... and if you want an amd system you use ddr(since there is no rambus/athlon chipset)
and until there is a rambus/athlon chipset i don't really think we can gague the real world implication of it...
either way i have better things to do with a few $100 than put it into a more expensive chipset/cpu/memory rig. if you have the extra money and the rambus system gives you what you want, then more power to you. overall, right now, you can't say either system is "the best" in ever possible catagory
I believe sex is highly over rated... unless it involves me
I think the point of that article is not that the Athlon is going to burn up.
There was a rumor being spread by some kids with AMD processors that the Pentium 4 runs at half speed whenever you do more than just checking email with your computer. They had taken a new feature in the Intel processor and manipulated it into a fault. Tom's article was only trying to explain what the feature is and why it's good, since many people did not understand what it was about. He was not in any way saying that your heatsinks are going to fall off and your processor will burn up, if you use an Athlon processor. It was not an attack on AMD, it was just an explaination of a new feature found in certain other processors.
About a year or so ago, intel was doing demo's of Q3A at fry's to show off the new P4. Economy was good, I had like 4k from PTO that I aquired between jobs so I said what the hell and dropped $1500 on a 850dgb board, processor, case and 128 of ram.
I gotta say, this stuff is hot, my friends have all gone off and bought gforce3's, amd's with DDR. I thought these new cards/systems would have score winmarks well above my own (around 3800 with a gforce2gts) but I was surprised to see they only score 1000 or so more than me.
Out of curiosity, we put one of those GF3's in my system. Without fail I would score about 400 to come in around 6300 3dmarks above my buddies amd1.6. My P4 is just 1.4. Yet even with a lower clockrate the memory bandwidth made a huge difference.
I'm not trying to cause a ruckus here, anyone with deep enough pockets (or access to enough systems) can just as easily do the same testing I did. Bottom line whether or not the moderators like it is rambus systems do provide the absolute best possible performance in 3D gaming. It certainly was expensive when it came out but now with the falling prices of all ram, it's within reach of anyone that want's that extra "oomph" in thier system.
Does anyone know of any AMD boards that use rambus? I'm sorta curious what kind of scores those get in comparison to the intel one's. Anyways thats my comment.
It wasn't a bad article... I mean, the facts -do- show that the p4 runs better with RDRAM, and he addresses the consequences of that quite well, and quite neutrally. For that I commend him.
But he does misrepresent some issues. For example, signal integrity issues. I can say with complete assurance that Rambus is loaded with signal integrity issues. These issues get -very bad- as the clock frequency goes up. Also Rambus is -not-, strictly speaking, a serial bus. First, it is 16 bits wide, while pure serial would be 1. Second, the depiction of a DIMM as being a unterminated stub with significant SI issues is correct, but this doesn't go away with rambus, and this definition of "serial" fails as well. While the signals do pass through a RIMM continuously, eliminating the RIMM itself as the source of major SI problems, you still have each and every RDRAM device itself acting as an unterminated stub, each of which causes reflections of its own. Especially for devices with tolerances as low as RDRAM, this can be difficult to manage. While in the balance I'd have to concede that at a given clock frequency RDRAM has the SI advantage, remember that RDRAM needs 4x the clock frequency of DDR to match bandwidth.
Or you could have 2 channels of rambus, and only need 2x the frequency. Well, 2 channel DDR is becoming a reality. Not only does nForce support it, Sledgehammer will as well. Neither of these are Intel platforms, but I would guess that going dual-channel would be a natural step for VIA and others competing with Intel chipsets. It would especially make sense for p4, as it would more than make up the memory bandwidth disparity that currently exists.
Speaking of nForce, another thing I take issue with is the suggestion that the nforce's DIMM-slot population problems are indicative that DDR is crippled by SI issues. I think more likely is that this was the first chipset designed by a company whose experience lies solely with graphics cards, on which the ram is directly soddered to the PCB. Lack of experience in the harsher SI conditions of a computer motherboard are to blame.
Speaking of DIMM population, it's hard for me to see only having 2 DIMM's on some boards as a particularly black mark for DDR... That leaves you with 2GB per channel, the same as RAMBUS.
So, he was right about some things, insightful on others, but the picture is -not- so clear-cut in the image of rambus Inc.
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QDR is coming out soon, (though they are calling it something else as I recall, no idea why, QDR is such a nice logical name, even the laymen can understand it) and it (seems to be?) but a mere advance of DDR technology.
:) (it never would, latency is too high, part of the base rambus technology)
:)
Not to mention how far up Nvidia has managed to scale DDR RAM. Heh. I would like to see RAMBUS get that.
RAMBUS would settle down good in a video toaster type of applicance, but that is about it. Video editing seems to be one of its few strong suits.
Besides, I would like to see a Motherboard that is halfway cheap and can support 3-4GigaBytes of RAMBUS RAM.
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The days of cheap memory are over.
They say this because of the huge expense needed to provide 512MB or more of ultra fast memory. But what if they added yet another level of "cache"?
Put in 128MB or more of super-fast RAM (faster than today's RDRAM or DDRAM, maybe using an exotic bus) backed by gigs of cheap, easy-to-make memory (PC266 DDRAM or slower). The cheap ram is still orders of magnitude faster than a disk drive. Manage them with hardware that does page swapping similar to virtual memory.
You could get good system performance and lower overall cost.
Well, not to make Tom's or RAMbus's argument for them... But just look at the benchmarks of the P4 2.6GHz/RMBS vs 3.0GHz/DDR vs 2.6GHz/DDR. It's clear that at those clock speeds RDRAM works much better with the P4. Much better. So if you are doing -anything- where such an increase is meaningfull -- which includes 3d games like UT -- then yes, you should go with the RDRAM.
But if what you get with DDR is "good enough", then of course you should go with that, because it is cheaper.
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Then the political aspect is ignored and he talks almost exclusively about technical issues about why Rambus might theoretically be better, and uses existing intel chipsets as evidence.
Hello? Answer the question, please? Has Intel ever come out with a non-crippled DDR chipset for the P4? How do Intel's DDR P4 chipsets compare to non-intel DDR P4 chipsets? (ARE there any non-intel P4 chipsets?)
How much of the problem is political, and how much of it is a real technical issue?
Thomas Pabst (who we all respect) posted scathing reviews not only of Rambus the company but also of Rambus the technology. If he is recanting he should do it in person, not through a couple of stoolies. By withdrawing such a controversial statement Tom's site is calling into question both the technical and political validity of his write-ups.
Don't get me wrong, THG rocks and I respect Tom's advice. He knows 10x more than me about hardware. But he should explain why this review is so opposed to the ones he wrote himself...
Now, unless you're doing video encoding, I don't know why you'd want a P4 in the first place...
:)
But to even entertain the thought in the first place, you can't be on an ultra-tight budget! So why try to save what will ultimately be a small % off the total price at the expense of performance?
It just doesn't make sense.
Though I still want to see a dual-channel DDR chipset for P4.
The enemies of Democracy are
Intel uses testers from schlumberger (their reps are quick to point that out). Typically, a tester cost anywhere from 1-10 million dollars + plus they require a lot of maintenance, calibration, etc. Basically, the faster and more pins you need, the more it cost.
I've worked with some schlumbeger 'KX' testers, they're a big pain in the ass, unreliable, and are badly designed: just shutting the thing off can break it!! (especially if you use the emergency off button).
There is another choice, however, you can use 'bist'(built-in self test) and have the chip basically test itself :-). This allows companies to get away with using cheaper, more reliable testers.
Um... How was that FUD?
It's true. If the heatsink falls off your Athlon it is toast. (note that just in the last week or so a board was released that supported the XP's thermal diode... but for all other boards/chips, you still get toast)
Tom isn't the genius a lot of people think he is (or that he'd want you to think), but that was not FUD.
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First, it looks to me like RDRAM is still about double the cost of SDRAM, according to Tom's Hardware's own price guide.
They have $93 for 512mb SDRAM and $175-250 for 512mb RDRAM.
My question is this: Let's say I have a choice between 512mb of SDRAM and 256mb of RDRAM. Would the SDRAM not almost always be faster because RAM, however slow, trumps swap space every time?
In other words, isn't the amount of memory I have more important than how fast it is?
Many moons ago, I had a SGI O2 workstation. Tremendous memory bandwidth, but memory that cost 10x more than anything else. As a result, it could be embarassed by lesser machines, since I couldn't afford to load it up with RAM.
I see Intel repeating the same mistake when it decided to focus on RDRAM.
Apple is putting L3 cache in their G4s so that the use of expensive RAM is confined to a relatively small and affordable amount. I can upgrade my PC133-equipped G4/450 dual processor to the latest 1ghz dual processor, put my 1.5gb RAM in it, and fly. That seems like a good compromise to me, maybe better than going to DDR, which I would have to buy new.
Thoughts?
D
I work for a test and measurement company and we sell logic analyzer tools for both DDR and RAMBUS. I service at least 1 site of each of the major computer manufactuers and I can tell you none of them are even considering RAMBUS. In fact, I can't remember the last time someone asked me about it. The only thing I have consulted customers on is the future of DDR. If anyone was interested in RAMBUS, I'd at least be hearing murmurs. Keep in mind I am only looking at computer manufactuers, not the 3rd party Asian motherboard manufactuers. Who knows what they are doing.
Though some might argue that the role of the preview option is to avoid such errors, I am inclined to agree with you. Either due to a lack of willingness to bother to preview, or simply because mistake initially escape your view, an "Edit" option would be most helpful. I'm almost entirely certain that many would argue that it would be abused (for instance, posting something insightful and receiving a bonus, and then swapping to an ASCII penis). Of course there are numerous safeguards that could be utilized to reduce the likelihood of this.
I'll take the Glad Bag!
Remember "Bring 'em on"? *sigh
Historically RDRAM has been plagued by cost, which has deterred its adoption, but this isn't why average reader of Slashdot dislikes it. They might claim that they think it's technically inferior (PC600 and PC800 have more latency than SDRAM, but PC1066 and PC1200 RDRAM will likely be out within the next year), I think a large majority of hatred of RDRAM comes from Intel and Rambus's business practicates.
Intel and Rambus were hoping to strangle the market into adopting RDRAM in order to hurt Intel's competitors, and when this failed (RDRAM's prices lead people to adopt PC133 and then DDR), they attempted to obtain royalties or sue developers of alternative memory technologies for patent infringement of one form or another.
they've relied alot on patents with a few shady practices. Your average slashdot reader doesnt know anything about ram design though, so they tend to just follow the loud critcizers..
-
It didn't stop a bunch of fools from seeing that and saying "oops, my heatsync fell off! AMD 5UX0RZ!!! 1N73L is 1337!". Understand this: When we're talking about people too retarded to put on a heatsync correctly, the facts are just an unfortunate mishap.
It's been a long time.
If price/performance was that important, you'd be using an AMD system, and RDRAM wouldn't come up. :)
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Yes, I realize he doesn't write most of the articles. But it's called Tom's Hardware. By virtue of the name alone, the quality of the content, regardless of who it is written by, reflects on him.
If he doesn't want to look like a dipshit, he shouldn't put dipshits on the payroll.
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To be honest, I really don't plan on buying another desktop system ever again. If needed, I'll build one out of spare/cheap parts. Why? Because I use my laptop anymore 99% of the time.
There will NEVER be a laptop with RIMMS in them because they are too damn hot. Unless the design of them drastically changes in some unknown way, this "NEVER" is a fact.
I think there are some DDR laptop solutions in the pipe now. Yet, there is the problem of the slower system bus speeds on laptops, so it will not matter much until that's fixed too.
rambus is disliked because they comitted fraud.
Fortunately, in May 2001 a Virginia jury convicted rambus of fraud.
Unfortunately, they fine the jury imposed on Rambus ($3.5m) was reduced to a mere fraction of the original penalty ($350,000) by state laws capping the limit of punitive damages.
A mere slap on the wrist for a company which acted so unethically.
In other words, isn't the amount of memory I have more important than how fast it is?
I think this is probably true.
However, as you point out, the price difference between RAMBUS and SDRAM is now very small. According to Sharky Extreme the difference between 512 MB of SDRAM and RDRAM is about $80, and DDR RAM (PC2100) is actually more expensive than RDRAM! So if you plan to put 2GB in your machine, SDRAM is appreciably cheaper, but if you plan to do that, you probably plan on some serious hardware as well, so you'll probably spend $3000+ (probably coulnd't get a motherboard that would take 2GB SDRAM anyway...).
My point is that both SDRAM, DDR RAM and RDRAM have come down in price dramatically in the past year (although memory prices seem to be on the rise again). The price difference is very small when compared to the total price of the machine, so why bother? I have nothing against DDR RAM, but it'll have to win on technical merit nowadays.
As an example, I had to specify and buy a PC for my job some weeks ago. Now, this PC will be running a very specialized application, and nothing else. No CD burning, MPEG/MP3 encoding, no image processing, and no games. I like a cool machine as much as the next guy, but I simply could not justify putting more than 512 MB in this machine. Same for the hard drive, 40GB should be more than enough. A decent monitor was a requirement however. So why save $80 on memory when we're spending $700+ on the monitor alone?
Summarizing: if 512 MB is enough for you, why bother? If it isn't enough, you'll likely spend a lot of dough anyway, so again, why bother?
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Please. SDRAM is the standard. DDR is entrenching into that market. Rambus? It's like the Mac - some people wonder, 'What's that?' while the techs laugh at people who have it.
Maybe. But, often it's the non-techs that make technical decisions, at least in a business environment. I'm sure companies like Dell are selling plenty of systems with RAMBUS in it.
Having a technologically superior product does not mean you'll succeed commercially. Having an inferior product does not mean you'll fail. Unfortunately.
MSN 8: Now Microsoft even has bugs in their ad campaigns.