Crucial PC2-8000 C5: Stock Memory Performance

While the Intel platform does not really allow for easily testing different memory speeds at the same CPU speed, our test Asus motherboard does provide a wide range of memory ratios that match available DDR2 memory. This allows end-users to select the memory ratio that matches their DDR2 memory speed if they wish, or to choose a speed value over or below the rated memory speed. For those reasons, we first tested all of the stock ratios at the fastest stable timings we could achieve at the given ratio. With ratios, processor speed remains constant at 3.46GHz and memory speed is varied by choosing different ratios.

Crucial (Stock Memory Ratios) - 2x1GB Double-Bank
CPU Ratio
at 3.47 GHz
Memory
Speed
Best
Timings
(Voltage)
Far Cry
(fps)
Sandra
Unbuffered
Sandra
Buffered
SuperPI 2M Mod 1.5
(seconds)
HL2 Lost Coast
(fps)
Quake 4 (fps)
(4:3) 400 DDR2 3-2-2-5
1.8V
60.8 INT 2820
FLT 2827
INT 5519
FLT 5548
88.6 82.6 68.8
(1:1) 533 DDR2 3-2-3-8
2.0V
61.4 INT 3494
FLT 3521
INT 6459
FLT 6467
86.2 87.9 73.4
(4:5) 667 DDR2 3-3-3-10
2.1V
62.2 INT 3961
FLT 4004
INT 6571
FLT 6565
85.5 88.7 75.7
(2:3) 800 DDR2 4-3-4-11
2.1V
62.6 INT 4211
FLT 4252
INT 6722
FLT 6702
84.9 89.5 76.5
(1:2) 1067 DDR2 4-4-5-14
2.35V
65.7 INT 4560
FLT 4632
INT 6836
FLT 6843
83.9 91.6 79.6
(3:5)
OC 300x13
1000 DDR2*
*Rated Speed
4-3-4-12
2.2V
73.3 INT 4989
FLT 5064
INT 7671
FLT 7658
74.9 101.3 87.8
Highest Mem Speed (1:2)
OC 271x13
1084 DDR2 5-4-5-15
2.35V
66.2 INT 4521
FLT 4587
INT 6905
FLT 6898
83 91.8 80.3
View Magnified Table

Since the Crucial Ballistix is also rated at DDR2-1000, the 1000 speed was tested for performance. To achieve that speed the 889 memory speed was selected at the standard 1066 FSB (266 setting quad pumped). The FSB was then overclocked to 300 (1200 FSB) resulting in a memory speed of DDR2-1000. The Ballistix performed much better than the rated timings of 5-5-5-15. The Ballistix memory was completely stable at DDR2-1000 at 4-3-4-12 timings. This matches the best memory timings we have found with DDR2-1000 as the timings are the same as OCZ EL PC2-8000 XTC.

While the Crucial generally matched the wide memory speed range of OCZ EL, the required memory timings at most memory speeds were a bit slower than those required by OCZ. This resulted in performance that was slightly slower than OCZ at most speeds. While Crucial, Buffalo, and OCZ all use the same Micron memory chips, each manufacturer "speed-bins" the chips using their own internal procedures. They also choose the PCB to use with the memory chips, and program the SPD for best performance. These additional steps result in some differences in performance with a given chip such as you are seeing in this review. Apparently OCZ squeezes a bit more performance out of these chips, although the performance advantage for OCZ is small.

The Crucial PC2-8000 topped out at DDR2-1084, which is slightly below DDR2-1100 achieved with the Buffalo and OCZ. However, the slower memory timings required at the top of the performance range make the speed around 800 to 1000 the best-performing range with any of these three DDR2-1000 rated memories. In that range the Crucial Ballistix is very competitive.

At the rated speed of DDR2-1000 the CPU is running at 13x300 or a 1200FSB. The CPU overclock and higher bus speed certainly contribute to the higher performance at DDR2-1000. Comparing non-overclocked CPU and bus speeds, the memory performance curve is linear, generally improving as speed increases. Where faster memory timings are possible (lower memory timing settings) there is a comparable improvement in memory performance.

Buffalo PC2-8000 C5: Stock Memory Performance DDR2 400 (4:3) Performance
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  • Wesley Fink - Monday, July 10, 2006 - link

    Crucial has advised AnandTech that "all of Crucial's memory products come with a lifetime warranty". We have updated the review to reflect this information on the Crucial warranty.
  • MacGuffin - Saturday, July 8, 2006 - link

    quote:

    DDR2 1067 (2:3) Performance


    It should read DDR2 1067 (1:2) Performance.
    This needs to be fixed on Page 10, along with the link on Page 9 that points to page 10, and the Article Index drop-down list.

    Excellent Review, nonetheless.
  • JarredWalton - Saturday, July 8, 2006 - link

    Fixed, thanks. :)
  • PLaYaHaTeD - Saturday, July 8, 2006 - link

    I thought since the front side bus of the 965 is 1066, it would be the 'Holy Grail' to have the memory running at 1066 as well. Wouldnt this make it synchronous again? What am i missing?
  • MacGuffin - Saturday, July 8, 2006 - link

    Synchronous Operation (meaning FSB:DRAM Ratio at 1:1)
    266MHz FSB -> 266MHz RAM Speed -> 533MHz DDR2

    The 1:2 Divider (which isn't synchronous) yields 1066MHz
    266MHz FSB -> 533MHz RAM Speed -> 1066MHz DDR2

    Am I right or have I gotten it wrong? I haven't used Intel since I got this Socket 754 I am typing on.
  • poohbear - Friday, July 7, 2006 - link

    hello, just wanna clarify if the a64 can actually use any of the extra bandwidth provided by ddr2 800+? is it only for bragging rights or is the a64 actually saturated for memory bandwidth & therefore this higher bandwidth provides performance improvements? thanks in advance.
  • Wesley Fink - Friday, July 7, 2006 - link

    The A64 does exhibit tremendous DDR2 bandwidth with the on-chip DDR2 memory controller, and memory bandwidth continues to improve as speed goes up. However, as we found in our testing of the AM2 in the DDR2 vs. DDR article, the AM2 design is not memory bandwidth starved, and the extra memory bandwidth makes almost no difference in real-world performance on the current AM2 platform. The improved memory bandwidth may make more of a difference in future AM2 designs.
  • lopri - Friday, July 7, 2006 - link

    I thought this issue was mentioned in the article but I couldn't find it when I re-read it. I know on intel system the memory running slower than 1:1 will result in small penalty, but how about memory running faster than FSB? I vaguely remember that I've heard somewhere it's better than 1:1 cause that way memory "pushes" or "rushes to" FSB. Another theory I've heard is that faster memory can make up for possible performance loss on FSB subsystem, leading to less CPU idle time. According to this review, regardless the ratio, the performance seems to increase linearly to memory speed increase.

    So the questions being:

    1. Is 1:1 the most ideal ratio without "waste"?
    2. Or a slightly higher memory speed than FSB (such as 4:5) better than 1:1, preventing possible CPU idle time and "pushing" the data at the same time?
    3. Or under the same CPU/FSB speed, the faster the memory the better the performance - indefinitely, taking advantage of faster memory speed?

    I would think No.3 doesn't make sense because of the very FSB. In the end the FSB has been what's limiting both CPU and memory on Intel system. How could the performance get benefit from 3:5? In an ideal world there should be waste of 2. (5 - 3 = 2) Is the performance even better with 1:2? I can't imagine the FSB system being only 50% efficient, but is that the case?
  • Gary Key - Saturday, July 8, 2006 - link

    Lopri,

    Please email me about this subject. Short story is 1:1 or 4:5 are your best ratios for the Intel platform at this time although this will change depending your choice of Conroe model. We will go over this in more detail shortly and I will respond here further once I complete some article testing.

    Thanks,
    Gary
  • Locust - Friday, July 7, 2006 - link

    Very good article, but I have a question. How come you guys did not review Corsair's PC8500 memory modules. I have been using 2GB kit(2x1GB) for over a month and getting timings comparable to OCZ's. DDR2 800 runs at 3-3-3-5 memory settings on same mobo.
    Best si DDR 1000 @ 4-4-3-8 @ 2.2 recommended voltage.

    Good to see more vendors offering these memory speeds, now let's just hope prices will get under $400 :-)

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