DDR3 RAM Explained

Das Capitolin sends us to Benchmark Reviews for an in-depth feature on DDR3 memory that begins: "These are uncertain financial times we live in today, and the rise and fall of our economy has had [a] direct [effect] on consumer spending. It has already been one full year now that DDR3 has been patiently waiting for the enthusiast community to give it proper consideration, yet [its] success is still undermined by misconceptions and high price. Benchmark Reviews has been testing DDR3 more actively than anyone. ... Sadly, it might take an article like this to open the eyes of my fellow hardware enthusiast[s] and overclocker[s], because it seems like DDR3 is the technology nobody wants [badly] enough to learn about. Pity, because overclocking is what it's all about."

Just a tad over the top?

[florin]

This article was rather amusing, at times I wasn't quite sure if the author was serious, with statements like:

One particularly important new change introduced with DDR3 is in the improved prefetch buffer: up from DDR2's four bits to an astounding eight bits per cycle.

Woo I think I wet my pants there. But the author seems genuinely excited about this technology. I mean:

DDR3 is very similar to the advancement of jet propulsion over prop-style aircraft, and an entirely new dimension of possibility is made available.

Hahaha

How about a DDR2 versus DDR3 chart?

[PoderOmega]

Great, now that I know how well certain DDR3 chips overclock, can I see how DDR3 compares to DDR2 in terms of raw performance and overclocking ability? I'm not an expert on how DDR2 works, so DDR3 could be better explained to me by showing me how it is better than DDR2.

Memory Bandwidth...

[maz2331]

Memory bandwidth is not problem right now. I/O is too slow. We need faster disks and LANs first.

Re:Memory Bandwidth...

[klapaucjusz]

We need faster disks and LANs first.

LANs are already fast -- when did you last saturate a GigE switch ? Right now, for most applications, the bottleneck is in the disk.

Teenage enthusiasm

[klapaucjusz]

It's always nice to see a tech writer full of teenage enthusiasm, but this article goes a little over the top.

It's supposed to be an article about a performance enhancement, and there's barely any performance values at all (except for the theoretical peak throughputs on page 3, and we know how much that means).

I think what the guy really wanted was to write about planes, not about computer hardware.

DDR3 simply picks up speed where DDR2 left off... which is as accurate as saying an airplane picks up where a kite left off.

DDR2 technology is no better prepared to reach higher speeds than a propeller airplane is capable of breaking the sound barrier;

DDR3 is very similar to the advancement of jet propulsion over prop-style aircraft,

Re:Overclockers

[DAldredge]

Because some value stability over speed.

Re:Just a tad over the top?

[King_TJ]

Whether or not the author was really serious, I think about the only really worthwhile comments of his might have been related to the "uncertain economy".

Right now, all too many people I know are finding themselves out of jobs, with no good-paying alternatives in sight. I just attended my girlfriend's college graduation ceremony yesterday afternoon, and the guy sitting behind us was a 40-something year old who decided to go back to school last semester, because he couldn't make it anymore in the construction business. He said he worked in construction for 18 years, and until 3 years ago, it was a good career for him. But in the last few years, things have gotten so bad, many people are resorting to selling off the trucks and equipment they used in their trade, just to keep the bills paid and to stay afloat. They're seeing their work dwindle to the point where they can do it as a side job, but can't guarantee they're always busy. Therefore, he finally decided to go back to school and start a new career path.

My g/f is in a similar dilemma. Here is she. fresh out of school with a degree in psychology, and really can't do a thing with it except continue on to earn a Masters' in psych. After that, she could open her own practice (MORE $'s on top of huge student loan debt!), or possibly partner with someone else - with results varying depending on what part of the country you decide to live in. She's thinking about going for a double major, with the 2nd. one in business .... because at least the internships for MBAs seem plentiful and promising right now.

Anyway ... my point is, most people just aren't going to be as "free" with their spending money as they were when they were sure their good-paying job was there for them. Playing with stuff like DDR3 vs. DDR2 amounts to "unnecessary entertainment" for the computer hobbyist, really. You can get a plenty fast PC running regular old DDR2 memory that will do whatever you need done. Buying into anything else, just for the sake of "overclocking" amounts to tinkering and computer hot-rodding for the fun of benchmarking and seeing how high a number you can get. It's not a practical activity when finances are uncertain or possibly very limited.

What about the 4GB limit in Vista 32?

[plusser]

The problem with sales of DDR3 is probably down to the fact that most computers are being sold with versions of Vista 32. To really make a difference with faster SRAM would probably also mean having a larger amount of SRAM. But the problem is Vista 32 only addresses just under 4GB of SRAM. As many computers for the home market max out by being supplied with 4GB of SRAM as new, the computers are effectively un-upgradable unless a different operating system is used. This leaves an interesting situation:- 1. Run Vista 64 - but then a large portion of hardware and software will not work as you cannot sign unapproved drivers. 2. Run Linux 3. Buy a MAC And there is the problem, the alternatives to using DDR3 are in fact called using a different operating system and adding standard DDR2 memory, which is more cost effective that paying the extra for the DDR3 SRAM. The only area I could possibly see DDR3 technology in the commercial hardware is in cutting edge graphics cards, where performance is everything. Unfortunately, as Vista 32 is already at is technology limit and that many potential users of this technology will baulk at the price, I can see games console manufacturers adopting this technology before the general PC market.

Re:Overclockers

[lukas84]

You're still lacking the source for

* BIOS
* BMC
* WLAN Card
* Disk Controllers

etc. pp.

Using His Jet Analogy

[nick_davison]

He's like a jet engine supporter immediately after World War II:

"Jet engines are inherrently capable of much greater speeds than propeller engines!"

"OK, so show me one that goes much faster than the prop driven spitfire?"

"Well, uh, there's the Gloster Meteor!"

"It does about 500mph*, right? That's not bad compared to the Spitfire XIX's 460mph. But there are tons of Spitfires out there, available cheaply vs. paying several times the cost for the Meteor for about a 10% speed improvement." *note: F-3 variant, not the "overclocked" tweaked versions that set speed records.

"Well, but the point isn't that it's better today. It's a better technology! It'll be better in the future! Props will never go supersonic. Jets can potentially go several times supersonic."

"That is cool. Doesn't really help me today though, does it? I'm still paying several times the cost for a small improvement, today."

"Yeah, but if you don't buy jets now, how will their prices ever come down? How will we ever reach the heady perfection they're capable of?"

"Again, not helping me today, is it?"

"But! But! It's really cool!"

Yes, the technology shows promise. But its future promise with only small increases today doesn't justify its current high cost.

If more people bought it, the cost would come down over time and more investment would mean unlocking more of that promise. Which is great in the future but gives you very little today in exchange for that high cost.

The argument he seems to be making is that everyone should adopt it right now, not because it actually gets them much for their money but because their investment will enable him to buy even faster stuff for a lower price later.

Not really compelling.

Re:Overclockers

[Anonymous Coward]

I dont know what retard modded you insightful. Anyone with even the slightest understanding of overclocking knows that you don't overclock to the point of instability.

Way to go Moderators.

Re:Just a tad over the top?

[mobby_6kl]

Well, what the hell did your girlfriend expect to do with a psychology degree in the first place? ;)

Back to RAM though, I don't see how this is any different than with DDR and DDR2. At first, the new technology was barely faster (sometimes not at all) then the old one, was not very widely supported, and of course cost more. I don't see why this should be any different now with DDR2 and DDR3. A slowdown in the US economy isn't going to bring technological progress to a halt.

Bending the facts, paid advertising?

[pnis]

This article seems to be paid advertising, with some bending of the facts.
And the fact is that the double prefetch buffer is the sole reason for the double bandwith and the double latency. As a matter of fact the speed of the individual memory chips on the ram module are the same as on ddr2 (see that table in the article, just divide the ddr3 clock by 2 to get the corresponding ddr2 speed) - but instead of reading 1 bit from 4 chips at once into the prefetch buffer (that is four bit prefetch buffer), they are reading from eight at once (so that's the 8 bit prefetch buffer), so double the amount of data can be read in the same time (hence the double bandwidth). However because the memory chips are the same speed as in ddr2, the time needed to program the individual chips stays the same - so because the clock is double the speed, it takes twice as many clocks to tell the individual chips which bit we want to fetch. And that bullshit about lower latencies is also not quite right: ddr3-1600 cl6 is the same latency as ddr2-800 cl3 - and such modules have been sold for years.

Of course ddr3 is better, because it has higher bandwidth, and absolute latency is not worse than ddr2's. Also there are in deed technological advances (e.g. the lower voltage). But this article is still not exactly honest.

Re:Just a tad over the top? No ECC = NO buy

[Omnedon]

Failure at build is one thing. I have never had anything pass memtest and subsequently been passed on to the customer and *then* fail.

I have yet to have a customer offer a contract for a full ECC system, but I expect that type of customer to be ordering in the dozens or hundreds. For one machine or 100 I would still give 48 hours of memtest. For ECC I would still give 48 hours of memtest.

If you can recommend a better test, I am open to suggestions.

Re:Just a tad over the top?

[TheLink]

Actually I don't think DDR2 was (is?) significantly faster than DDR for normal PCs.

The only reason to buy DDR2 over DDR is because it is cheaper (and compatible with more stuff you want).

At the moment is DDR3 cheaper? No. The last I checked it's about 4X more expensive or more.

Who cares if RAR is 10% faster (just making up figures ;) ), because you use DDR3? If it's so expensive, most gamers would rather pump the extra money into their video card where they get more bang _nowadays_ especially with the new AMD/ATI vs Nvidia battle.

For people who need CPU power? They buy a higher end CPU instead or more DDR2 RAM.