DDR3 vs. DDR2

by Wesley Fink on May 15, 2007 2:40 PM EST
Memory Test Configuration

The comparison of DDR3 and DDR2 used exactly the same components in the same test bed wherever possible. For the fairest comparison to the P35, both the P5K and P5K3 motherboards were powered by an Intel E6420 processor running at a 1333 FSB (333 quad pumped). All that was required to do this was increase the base CPU bus to 333, leaving the default multiplier at 8. We did not even need to increase the CPU voltage and left it at the default setting. This simple setup allowed us to run the 2133MHz (8x266) Core 2 Duo E6420 at a new speed of 2666MHz. This is equivalent to an E6700 Core 2 Duo in speed. Due to issues with memory ratios on the P965 we were forced to use an E6700 for comparison. This CPU also runs at 2666MHz using a 10x266 configuration.

Memory Performance Test Configuration
Processor Intel Core 2 Duo E6420
(x2, 2.66GHz, 8x333, 4MB Unified Cache)
Intel Core 2 Duo E6700
(x2, 2.66GHz, 10x266, 4MB Unified Cache)
Intel Core 2 Quad Q6600
(x4; 2.4GHz, 9x266; 3.0GHz, 9x333; 2.66GHz, 8x333; 8MB Unified Cache)
RAM Corsair CM3X1024-1066C7
(2GB Kit - 2x1GB)
Wintec AmpX PC3-8500
(2GB Kit - 2x1GB)
Corsair Dominator CM2X1024-8888C4
(2GB Kit - 2x1GB)
Hard Drive Samsung 250GB SATA3.0Gbps (8MB Buffer)
System Platform Drivers Intel - 8.3.0.1013
Video Card Leadtek WinFast 7950GT 256MB
Video Drivers NVIDIA 93.71
CPU Cooling Intel Retail HSF
Power Supply Corsair HX620W
Motherboards ASUS P5K3 Deluxe (Intel P35 DDR3)
ASUS P5K Deluxe (Intel P35 DDR2)
ASUS P5B Deluxe (Intel P965 DDR2)
Operating System Windows XP Professional SP2
Bench Software SiSoft Sandra XI SP2
CPU-Z 1.39.4
CPU-Z 1.40
Everest 4.0
SuperPi 1.5
Far Cry - HOC River Demo

While memory timings were matched to the same memory speed wherever possible, there were a few settings where the chipsets did not allow a direct comparison. DDR3-800 runs at 6-6-6-15 timings. The P965 has options to set 6-6-6-15 timings but the board would not boot under any settings or voltage we fed it at 6-6-6 timings. The closest timings that would work on the P965 at 800 speed were 5-6-6-15. The P5K DDR2 board, based on the P35 chipset, would allow setiing and running 6-6-6-15 timings. This is reflected in our charts with the line ID of 5/6-6-6- for timings. We also tested DDR2 at the fastest timings it could achieve with complete stability on both the P5B Deluxe and P5K Deluxe. This was 3-3-3-9 at DDR2-800 and 4-4-3-11 at DDR2-1066.

It is a noteworthy advantage with the P35 chipset motherboards that every Core 2 Duo and Core 2 Quad processor we tested on the P35 boards ran at 1333 FSB speeds at the stock multiplier without the need to increase voltage. This is a significant, free, and pain-free overclock provided courtesy of the new 1333 bus speed option. The only exception to this was our top-line X6800 which did require a mild voltage boost to run at 333x11 (3.67GHz).

All of the CPUs listed above in our table are 1066 FSB processors, but all ran fine at 1333 FSB at default multiplier and default voltage. Of course this is the FSB frequency Intel will be introducing on their soon-to-be-announced processors. This little side effect will make the P35 with DDR2 a favorite overclockers' board with current Intel Core 2 Duo and Core 2 Quad processors. A $189 E6420 can perform even better than an E6700 just by selecting a 1333 bus on P35 and leaving everything else at default. Likewise, a $500 Q6600 will outperform the ~$1000 QX6700 with just a bus speed change.

This little side effect will certainly be noticed by Intel. We have to wonder how fast the 1066 processors may start disappearing with this kind of free, painless overclocking available with the new P35 boards.

DDR3 Memory and P35 motherboards Bandwidth and Memory Scaling
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  • Wesley Fink - Tuesday, May 15, 2007 - link

    Yes. The P965 would not boot witha a CAS setting of 6 even though it could be selected. So the P965 was tested at 5-6-6 timings. The same DDR2 on the P5K was tested at 6-6-6, which would work and also matched the DDR3 timings. We will clarify this in the article.
  • TA152H - Tuesday, May 15, 2007 - link

    OK, thanks.

    One thing I would suggest when you do the final tests for the Bearlake and DDR3 is to use the 2M processors as well. You'd expect the 4M cache to hide the differences better, obviously, so the 2M cache processors would be pretty interesting to see as well, if for no other reason to see how much the larger cache does mask the difference in the chipset and memory. Since Intel is planning on increasing cache sizes, it would be a pretty useful data point.
  • TA152H - Tuesday, May 15, 2007 - link

    You measured the performance of the memory, but why not take a power measurement of it as well. That is one of the draws of the technology, it uses lower voltage, and therefore should use a little less power and generate less heat. Both are significant.

    Good article though, I just wish that had been included.
  • kalrith - Tuesday, May 15, 2007 - link

    Page 2, second line of second-to-last paragraph says, "which is a 16% reduction form DDR2". "form" should be "from".

    Last page, fourth line of third-to-last paragraph says, "the shift to DDR2 may be further delayed". "DDR2" should be "DDR3".

    BTW, I found the article interesting, informative, enlightening, and unbiased (as usual).
  • Wesley Fink - Tuesday, May 15, 2007 - link

    Mild dyslexia and less-than smart built-in spell checkers always win :) Both errors are corrected. Thanks.

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