Does AM2's Performance Make Sense?
Assuming for a moment that the performance we're seeing here today is representative of what AMD will show off in 2 months, does it make sense? AMD has effectively doubled their memory bandwidth but they've seen virtually no increase in performance, other than in some very isolated situations.
If you'll remember back to the introduction of AMD's Revision E core, we did an article about how the new core brought support four new memory dividers allowing you to run at speeds up to DDR500 without overclocking your CPU or the rest of your system. In that article we looked at the overall performance benefit of DDR-500 over DDR-400 on a Socket-939 platform in a variety of situations. A recap of our performance results is below:
| Benchmark | Socket-939 (DDR-400) | Socket-939 (DDR-480) | % Advantage (DDR-480) |
| Multimedia Winstone 2004 | 41.9 | 42.7 | 2% |
| 3dsmax 6 | 2.78 | 2.80 | 1% |
| DivX 6.0 | 50.6 fps | 53.2 fps | 5% |
| WME9 | 4.22 fps | 4.28 fps | 1% |
| Quake 3 (10x7) | 121.9 fps | 127.2 fps | 4% |
| ScienceMark 2.0 (Bandwidth)* | 5378 MB/s | 5851 MB/s | 9% |
As you can see, given almost a 9% increase in memory bandwidth, we saw similarly small increases in overall performance. It would seem that the Athlon 64, at its current clock speeds, just simply isn't starved enough for memory bandwidth to benefit from an increase in bandwidth. You'll also see that the areas where faster DDR memory helped back then are pretty much the areas where DDR2-800 is showing gains today.
Based on our results from back then, if a 9% increase in memory bandwidth doesn't increase performance tremendously, then the 35% increase in bandwidth we see with DDR2-800 on AM2 shouldn't yield any more of a performance increase. Or simply put, yes, our AM2 performance numbers make sense.
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Thor33 - Monday, April 10, 2006 - link
It seems the test was done with the fastest memory available in fact is a PC2-8000 1000mhz rated. OCZ EL DDR2 PC2-8000 / 1000 MHz / Platinum XTC / Extreme Editionhttp://www.anandtech.com/memory/showdoc.aspx?i=273...">http://www.anandtech.com/memory/showdoc.aspx?i=273...
Unless there is a typo on the test memory utilized below is PC8000 drop down to work as PC2-6400?
Memory:
PC2-6400 OCZ PC8000 DDR2-800 4-5-4-15 (1GB x 2)
OCZ DDR-400 2-3-2 (1GB x 2)
The test should be a PC2-6400 which is DDR2-800 mhz rated memory. If this test is performed with an average memory maker DDR2 PC2-6400 memory the score will be even less impressive. This is worth mentioning.
Rated at DDR2-1000, this OCZ announces right off the bat that it is serious new memory. Past DDR2 has struggled to reach DDR2-1000, so rating this new OCZ at DDR2-1000 is a "look-at-me" announcement. The rated timings of 4-5-4-15 at DDR2-1000 are also exceptionally fast for DDR2 memory at that speed. By the way, for those of you who have trouble translating PC speed ratings to Memory Speeds, all you have to do is divide by 8. Thus PC2-8000 is DDR2-1000 speed, PC-5400 is DDR2-667 (results are approximate), PC2-6400 is DDR2-800, etc.
waldo - Monday, April 10, 2006 - link
I haven't heard anything about changes in regards to the opteron platform, or are they staying the same. I would assume they would change to use the ddr2 memory as well.I actually can't see how purchasing a new AM2 system is good for anyone, whether a new system or upgrading. With prices being higher, almost double, and parts being barely similar in performance with premium boards, memory, etc., it doesn't seem like a good idea for anyone to hop on early to the AM2 platform. Just seems like a waste of a lot of money. In this case, the latest is not the greatest.
bob661 - Monday, April 10, 2006 - link
Where are the double prices? The ram is more money but everything else looks to be the same. According to http://tinyurl.com/koapt">this, the prices for the CPU's are the same as current one's. I doubt the motherboards will cost more than the typical new release prices.petz - Monday, April 10, 2006 - link
What was the date code on the CPU? Why no screenshot showing that the CPU was at least recognized? The BIOS memory settings are meaningless if the CPU is not properly recognized. I would have done a disk benchmark, because the fact that the poorest result was from Business Winstone tells me that something was wrong in that department.Anand Lal Shimpi - Monday, April 10, 2006 - link
The shots of the chip itself were kept out of the review to protect our source for the chips obviously. A difference of 0.1 points in Business Winstone is within the normal margin of error (< 3%) for that benchmark, the difference itself is basically 0. The CPU was also recognized properly by the BIOS.Take care,
Anand
nicolasb - Monday, April 10, 2006 - link
It seems to me that socket AM2 is likely to be just a stepping stone. Current AMD processors don't need DDR2 - but the next generation will.Conroe seems likely to stamp all over AMD for a few months. The point when things will get interesting again is when we see quad-core processors begin to ship from both Intel and AMD.
AMD's architecture has been tuned for multi-processor systems right from the start. Post-Conroe quad-core chips may be a bit clunky - effectively two dual-core chips glued together, in the same kind of way that Pentium D is two single-core chips glued together. AMD may therefore regain the lead in the quad-core arena - if there are no other limiting factors, such as memory bandwidth.
If a dual-core chip is using barely half of the available memory bandwidth of DDR2-800, what that means is that a quad core chip will not be significantly limited by memory bandwidth. I think this is what AMD is planning: they will need DDR2 bandwidth for quad-core, and they want to switch over to it now to get all the bugs ironed out in time for K8L. So socket AM2 has no significance for the current generation of chips, and was never meant to have: it's merely preparation for 2007.
If this is true, then the fact that current chips use only half the available bandwidth may actually be deliberate, and something that won't change.
sprockkets - Monday, April 10, 2006 - link
I like your post.Remember the KT266 fiasco? Then KT266A, then KT333, then KT400?
Yeah, the KT266A killed everything, when the KT266 showed no performance gains and just like then, said memory bandwidth is useless for AMD Athlons.
Except the problem here is, to get an updated "chipset" or memory controller, you have to upgrade the processor and perhaps the board, and AMD has already done 3 rev of the processor.
MrKaz - Monday, April 10, 2006 - link
PC133 SDRAM > DDR at early stagePC133 SDRAM > RDRAM at early stage
It will improve on next revision I bet, I was expecting 0% improve.
This is just a RAM type exchange.
You AMD systems users must show appreciation to AMD for the excellent platform they developed.
With Intel each time there is a memory speed bump, you "have" to upgrade the motherboard because of the memory controller on the chipset, even if Intel decides to keep the same socket. How many times since DDR266 have Intel “forced” people to upgrade motherboard/chipset in order to catch up every time there is a memory speed bump?
Even at the same RAM speed Intel “offers” (example) 865 and 875 chipsets where one is faster than the other with the same RAM?
Since AMD integrates the memory controller, you never get problems like that. AMD integrated memory controller is compatible with DDR 266 to 400 (unofficial 433,466,500).
With DDR2, you will get 533,667,800 (unofficial 933, 1066).
You always keep the same board and RAM. The processor is the only that changes.
If AMD didn’t get socket 754, and only 940 or 939 we where looking at the perfect computer platform.
Calin - Monday, April 10, 2006 - link
RDRAM was a very bad choice for the processors to which was first mated. Pentium !!!, like the Athlons of today, fare better on low latency lower bandwidth memory than on high latency high bandwidth memory (as RDRAM was). However, RDRAM has its place in small devices - where you can not fit all of the 168 pins of SDR memory, or all of the 180+ of the DDR memory.Pentium 4 was doing very well on RDRAM, dual RDRAM was quite a bit faster than dual SDR or single DDR. There was a time when intel 850 with dual RDRAM was the high mark in the chipsets
flyck - Monday, April 10, 2006 - link
RDRam had a LOWER latency then DDR.Mainly because of the superior chipset design (which had less internal latency).