DDR2/DDR3 Overlap Speeds
In Kingston Launches Low-Latency DDR3, memory performance was compared at the DDR2 and DDR3 overlap speeds of 800 and 1066 MHz. With the retesting of memory in the new test bed it was worthwhile to compare memory, at least in this initial review, at the overlap speeds. This presents the opportunity of seeing how top DDR3 performance compares to the DDR2 performance with which you are familiar.
At 800 MHz, DDR2 is capable of 3-3-3 timings, while DDR3 is limited to CAS 5 in the ASUS P5K3 Deluxe BIOS. With that severe timing limitation, which is the result of the much higher speeds available with DDR3, the DDR2 memory is generally the fastest solution. The latest Elpida (Kingston) and Micron Z9 (OCZ) chips still beat the last generation DDR2 in the Intel P965 motherboard in almost every case. However, the latest P35 Intel chipset driving DDR2 instead of DDR3 is still the best performer at 800 MHz - simply due to the advantage of CAS 3 compared to CAS 5 timings.
At the overlap speed of 1066 DDR2 still enjoys a timings advantage over DDR3 on the ASUS board. The fastest DDR3 CAS timings of 5 limits the best DDR3 timings to 5-4-3 compared to DDR2 at 4-4-3 with Corsair Dominator DDR2. Even with the timings advantage, DDR2 is only truly the better performer when running on the P35 chipset. The advantage for DDR2 here is very small to non-existent, however, as DDR3 results top a couple of the P35 DDR2-1066 benchmarks and the Elpida and Micron Z9 generally outperform DDR2/P965 across the board.
By 1333 the timing advantage for DDR2 is gone and DDR3 pulls clearly in the lead in all benchmarks. The Micron Z9-based memories top the 1333 performance charts in all benchmarks, and this is just the beginning of a range that extends to DDR3-2000 and beyond for some of these memories. Keep in mind that memory in these three charts are all running at the same 2.66GHz CPU speed, and that only the memory speed has been changed by varying ratios. It should be obvious in these results why Intel elected to move to the 1333 bus and the faster speeds of DDR3 memory.
Going up from DDR3-1333 to DDR3-1600, DDR3-2000 and beyond further extends the performance lead for DDR3 as you will see in the next three pages of DDR3 performance results on the same benchmarks. With the change to the 3.0GHz processor speed to allow memory tests through DDR3-2000 at the same CPU speed, all benchmarks were rerun at the 3.0GHz CPU speed with 800, 1066, and 1333 memory speeds. This allows a linear comparison of DDR3 memory at all available memory speeds while the CPU speed remains at a constant 3.0GHz.
For this and subsequent DDR3 reviews, DDR3 performance will be compared at 800, 1066, 1333, 1600, 2000, and the highest memory speed for the tested memory. 1000 is the logical base for the 333 strap, as is 1666, but current ratios limit realistic benchmarking to the 1066 and 1600 reference speeds. We will change to the 1000 and 1666 speed options as soon as available memory ratios in the BIOS allow a more convenient means to select 1000 and 1666 as memory speeds at a consistent processor speed. Those ratios are not currently available in the ASUS P5K3 Deluxe BIOS - or in any other DDR3 compatible motherboards at present.
In Kingston Launches Low-Latency DDR3, memory performance was compared at the DDR2 and DDR3 overlap speeds of 800 and 1066 MHz. With the retesting of memory in the new test bed it was worthwhile to compare memory, at least in this initial review, at the overlap speeds. This presents the opportunity of seeing how top DDR3 performance compares to the DDR2 performance with which you are familiar.
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| Click to enlarge |
At 800 MHz, DDR2 is capable of 3-3-3 timings, while DDR3 is limited to CAS 5 in the ASUS P5K3 Deluxe BIOS. With that severe timing limitation, which is the result of the much higher speeds available with DDR3, the DDR2 memory is generally the fastest solution. The latest Elpida (Kingston) and Micron Z9 (OCZ) chips still beat the last generation DDR2 in the Intel P965 motherboard in almost every case. However, the latest P35 Intel chipset driving DDR2 instead of DDR3 is still the best performer at 800 MHz - simply due to the advantage of CAS 3 compared to CAS 5 timings.
 |
| Click to enlarge |
At the overlap speed of 1066 DDR2 still enjoys a timings advantage over DDR3 on the ASUS board. The fastest DDR3 CAS timings of 5 limits the best DDR3 timings to 5-4-3 compared to DDR2 at 4-4-3 with Corsair Dominator DDR2. Even with the timings advantage, DDR2 is only truly the better performer when running on the P35 chipset. The advantage for DDR2 here is very small to non-existent, however, as DDR3 results top a couple of the P35 DDR2-1066 benchmarks and the Elpida and Micron Z9 generally outperform DDR2/P965 across the board.
 |
| Click to enlarge |
By 1333 the timing advantage for DDR2 is gone and DDR3 pulls clearly in the lead in all benchmarks. The Micron Z9-based memories top the 1333 performance charts in all benchmarks, and this is just the beginning of a range that extends to DDR3-2000 and beyond for some of these memories. Keep in mind that memory in these three charts are all running at the same 2.66GHz CPU speed, and that only the memory speed has been changed by varying ratios. It should be obvious in these results why Intel elected to move to the 1333 bus and the faster speeds of DDR3 memory.
Going up from DDR3-1333 to DDR3-1600, DDR3-2000 and beyond further extends the performance lead for DDR3 as you will see in the next three pages of DDR3 performance results on the same benchmarks. With the change to the 3.0GHz processor speed to allow memory tests through DDR3-2000 at the same CPU speed, all benchmarks were rerun at the 3.0GHz CPU speed with 800, 1066, and 1333 memory speeds. This allows a linear comparison of DDR3 memory at all available memory speeds while the CPU speed remains at a constant 3.0GHz.
For this and subsequent DDR3 reviews, DDR3 performance will be compared at 800, 1066, 1333, 1600, 2000, and the highest memory speed for the tested memory. 1000 is the logical base for the 333 strap, as is 1666, but current ratios limit realistic benchmarking to the 1066 and 1600 reference speeds. We will change to the 1000 and 1666 speed options as soon as available memory ratios in the BIOS allow a more convenient means to select 1000 and 1666 as memory speeds at a consistent processor speed. Those ratios are not currently available in the ASUS P5K3 Deluxe BIOS - or in any other DDR3 compatible motherboards at present.
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Mithan - Wednesday, August 1, 2007 - link
I am guessing these games were run at 800x600, which is fairly standard for memory tests?IF that is the case, then all this article does is prove once again why over-spending on memory is not the best use of your dollars (except in the case of over-clocking)
My point is this:
Farcry going from 112 to 122 FPS is probably being done at 800x600 or 1024x768.
Bump that resolution up to 1600x1200 or 1920x1200, and that becomes 1 or 2 frames per second difference.
My point is that the article should articulate this difference better.
MadBoris - Wednesday, August 1, 2007 - link
From a testing perspective of any hardware among each other, you have to isolate and remove the other bottlenecks. That should be done and is of course common sense. As you state, the main goal of these types of articles should at their very foundation stay focused on real world performance impact. Otherwise it looks too much like technology promotion and they lose their actual value to the reader. They don't have to go "real world" overboard, but I think that should be the consistent goal of hardware reviews.
Test info would be nice.
In the same vein of real world impact, the comparison should never have been between DDR3@800 compared to DDR3@2000. That's not even really applicable, the upgrade path isn't from DDR3 800, so I am not sure why the particular comparison was even made. The comparison at the very least, needs to be to current DDR2 offerings. The best case performance that DDR3 can provide right now is actually around 3 - 5 percent from current DDR2 offerings under those specific game tests (as I mentioned earlier), whatever those settings were.
Obviously testing these memory comparisons isn't simple from an apples to apples standpoint especially with limited time, so I am just glad Anandtech is getting in there and doing the testing and making their findings known. :)
Wesley Fink - Wednesday, August 1, 2007 - link
Factoring in the slower performance of current 965/975 boards on p.4 of the article, you will see that DDR3-800 on the P35 clearly beats DDR2-800 on the P965 platform. In fact, DDR3 is generally faster than DDR2-1066 at 4-4-3 timings on the P965 (the only exception being Far Cry). Taking that into account our broad statement that current DDR3 can provide as much as an 8% to 10% real world performance improvement over current DDR2 systems is certainly fair.Wesley Fink - Wednesday, August 1, 2007 - link
DDR2-800 is the fastest official JEDEC spec for DDR2, and memory running at 3-3-3 at that resolution is common among better DDR2. It is among the fastest DDR2 performance due to the fast timings. The fastest DDR2 can reach 1066 at slower timings but it cannot reach 1333.Similarly we would compare to DDR-400 at 2-2-2 looking at DDR, since this was the fastest JEDEC speed looking back at DDR. DDR3 starts at 800 and goes officially at the present time to DDR3-1600. It will likley go higher in the future.
We have compared DDR3 to one of the fastest DDR2 memories ever made at the fastest timings available for DDR2 at both 800 and 1066 in the overlap speed results on p. 4. We also did not really factor in the fact that DDR2 runs slower on the P965, P975, and other current boards than it does on the DDR2 version of the current P35 chipset.
NegativeEntropy - Tuesday, July 31, 2007 - link
I read through the article and (quickly) double checked the test config and gaming pages, but I did not see the settings the games were tested at?Wesley Fink - Wednesday, August 1, 2007 - link
All games were run at 1280x1024. That has been in past commentary, but was dropped somewhere along the way. We will add that info to the game results page.Jodiuh - Wednesday, August 1, 2007 - link
Unfortunately, you're right in the $$ issues. Those of us that would be willing to pay 2-3 times the amount for 10% gaming improvement would be better off w/ a better GPU, or even a Q66/X32 CPU for games like Supcom.Would you mind guessing what perf improvement would come from running @ say 1600x1200 or greater + 8xQ/6x AA? It'd be even less, no?
chizow - Tuesday, July 31, 2007 - link
Another underwhelming and unnecessary "update" to memory specifications. Just another example of the memory mfgs and motherboard makers forcing people to upgrade every few years for marginal performance gains. Oh well, good news is DDR2 is dirt cheap and has been for a while.LTG - Tuesday, July 31, 2007 - link
I started the complaint thread last time about the lack of comparable results, so I want to say this time:Great work, excellent article.
I was a little taken aback by your heated reaction to criticism, due to the fact that I didn't provide the solution, but hey, that's kind of human nature and I'm sure I've done it before.
The main point here is that AT not only has the best writers of any tech site, but also the only site where they are not afraid to allow feedback and actually engage debate on the issues.
Tech articles are near impossible to get perfect, because there is so many details to know and new things are discovered across the net every hour. But don't every get discouraged, the effort is all appreciated.
LTG
Wesley Fink - Tuesday, July 31, 2007 - link
Thank you for your comments. They are sincerely appreciated.