Abit AA8: Overclocking and Stress Testing

FSB Overclocking Results

Front Side Bus Overclocking Testbed
Processor: Pentium 4 Prescott LGA 775
2.8GHz
CPU Voltage: 1.3875V (default)
Cooling: Thermaltake Jungle 502
Power Supply: HiPro 470W
Maximum OC: 260FSB (+30%)

Like the earlier Socket 478 Pentium 4 processors, the LGA 775 CPUs are multiplier locked. Therefore, the only way to overclock the CPU is to increase the FSB. Unfortunately, the PCI Express bus is not locked, or rather, fixing the frequency tends to limit the overclocking of the 925X. Abit manipulates the PCIe frequency with µGuru during boot to achieve higher overclocks. For more information on how Abit manages to overclock the AA8, please check Breaking Intel's Overclock Lock: The REAL Story.

The AA8 was able to achieve a reach for FSB of 260, a 30% overclock, with an ATI X800 XT and SATA hard drive. Abit was able to achieve close to the same overclock with the nVidia 6800 Ultra at 258. The nVidia is generally less tolerant of out-of-spec PCIe frequency, so this performance is really excellent.

Memory Stress Test Results:

The memory stress test measures the ability of the Abit AA8 to operate at its officially supported memory frequency (533MHz DDR2), at the best performing memory timings that Crucial/Micron PC2-4300U will support. Memory stress testing was conducted by running DDR2 at 533MHz (stock 3:4 ratio) with 2 DIMM slots operating in Dual-Channel mode.

Stable DDR533 Timings - 2 DIMMs
(2/4 DIMMs - 1 Dual-Channel Bank)
Clock Speed: 266MHz
Timing Mode: 3:4 (200:266 - Default)
CAS Latency: 3.0
Bank Interleave: Auto
RAS to CAS Delay: 3
RAS Precharge: 3
Cycle Time (tRAS): 10*
Command Rate: N/A
*SPD (Auto) timings for DDR2 are normally 4-4-4-12 at DDR2-533. A tRAS setting of 12 is normal. We ran a series of tests to measure memory bandwidth, and found the tRAS setting made very little difference in the performance of DDR2. The most effective range of tRAS was 8 to 13 for DDR2 on the 925X chipset, so a tRAS of 10 was chosen for benchmarking.

The Abit AA8 DuraMAX was completely stable with 2 DIMMs in Dual-Channel at the DDR2 settings of 3-3-3-10 at 1.8V default voltage. These are much faster settings than the DDR2 SPD and rated timings of 4-4-4-12.

Filling all four available memory slots is more strenuous on the memory sub-system than testing 2 DDR2 modules on a motherboard.

Stable DDR533 Timings - 4 DIMMs
(4/4 DIMMs - 2 Dual-Channel Banks)
Clock Speed: 266MHz
Timing Mode: 3:4 (200:266 - Default)
CAS Latency: 4.0
Bank Interleave: Auto
RAS to CAS Delay: 3
RAS Precharge: 3
Cycle Time (tRAS): 10
Command Rate: N/A

DDR has a long benchmarking history that makes it easier to figure out where to go with memory timings. We are still in the learning curve with DDR2, and the old DDR patterns just do not work in DDR2. We found that no matter what the rest of the settings, 4 DIMMs with DDR2 required CAS 4 for stability. Timings like 3-4-3 or 3-4-4 appeared to work fine, and then we were suddenly facing hard drive corruption. Our advice for now is to use CAS 4 with 4 DIMMs for stability, although 4-3-3 timings did work fine on many of the test boards. If you plan to try raising voltage to attempt lower CAS with 4 DIMMs, then please backup your system first. Our test beds gave no warning at all before hard drive corruption with overly aggressive timings using 4 DIMMs.

Abit AA8: Features and Layout Asus P5AD2 Premium: Features and Layout
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  • JustAnAverageGuy - Thursday, August 12, 2004 - link

    On the Gigabyte 8ANXP-D:

    Page 10

    Memory Slots Four 240-pin DDR2 Slots

    Gigabyte provides 6 DIMM slots, but the total memory and number of sides that can be used is the same as the other boards in the roundup.
  • JustAnAverageGuy - Thursday, August 12, 2004 - link

    Typo page 5:

    "The memory stress test measures the ability of the Abit AA8 to"

    should read Asus P5AD2. :)

    only on page 5, may be more.
  • l3ored - Thursday, August 12, 2004 - link

    allright, point taken. howabout testing lower lga775 cpus and combining the results with 939 scores?
  • Wesley Fink - Thursday, August 12, 2004 - link

    #5 - You're welcome.

    We also ran and reported the rest of our standard motherboard tests, which included Business and Multimedia Content Creation Winstones and Media encoding (which Intel won by a small margin).

    As we stated in the review the only reason we did not include our standard SPECviewperf 7.1.1 benchmarks is because we have seen variations of up to 100% in SPECviewperf results with certain 925X boards. We don't believe these results are real, and we are trying to find answers for these variations in benchmark results. Until we find some answers, publishing the workstation benchmark results would not really reveal anything about the performance of the 925X boards we are testing.

    The FX53, Intel 925X, and Intel 915 results are included for reference and completeness. We are comparing five 925X motherboards in performance, and we do not mean to detract from that comparison with AMD Socket 939 benchmarks. Please consider the 939 results to be a frame of reference.
  • AnnoyedGrunt - Thursday, August 12, 2004 - link

    From what I can see, the P4 560 is about $750, so that puts it right between the 3800+ (about $650) and the FX-53 (about $850) in price. It would be nice to add the 3800+ scores (if you have any) to that review just so we could see how the price/performance of the 560, 3800+, and FX-53 compare.

    -D'oh!
  • Shimmishim - Thursday, August 12, 2004 - link

    #2 - Achieving a 4 ghz overclock on a pentium is nothing to sneeze at... i think 3.8 may be possible on air but 4.2 is really pushing.

    As much as a lot of us would love to see overclocked processor results, i think it's best that they only show stock clock results as they are easier to compare...

    #3 - Its hard to say how fair it is to use a FX-53 against the 3.6 ghz 775 chip... but if you think about it, they are comparing the top end pentium 775 skt (new pin count) vs. the top of the line A64 939 skt (new pin count)..

    Both are also 1 megs of L2 even though the extra cache doesn't help the A64 greatly.

    Maybe a 3800+ would have been better comparison but i think he was trying to make things as easy to compare as possible...

    Even if he had used a 3800+ or even a 3700+ i don't think the gaming results would have been that much different... we all know that the A64's dominate in gaming.

    maybe some more tests besides gaming would have been better...

    but all in all...

    thank you Wes for a good article!
  • Wesley Fink - Thursday, August 12, 2004 - link

    #3 - The 3.6 is the fastest Intel processor. If you will check our launch reviews you will see the 3.6 outperformed the 3.4EE. We are indeed comparing the best performing Intel - the 3.6 - to the best performing AMD - FX53.

    Prior to the 3.6, the 3.4EE was the fastest Intel CPU.
  • l3ored - Thursday, August 12, 2004 - link

    lately i've been noticing unfair comparisons between intel and amd, in this article, high end processors are being compared with the top of the line from amd. this isnt really helpful to anyone, so please go back to the old anandtech way.
  • Anemone - Thursday, August 12, 2004 - link

    Nice article !

    If I could have had one extra wish it would have been to show a set of test charts with a moderate oc on them, think that would put the FX @ 2.6-2.7 and the P4 560's @ 4.2-4.3.

    If the boards can overclock, and the 939's can too, where does it all land for those using just normal or at most water oc'ing.

    No worry, these wishes do not detract from a very nice article.

    Thank you
  • stickybytes - Thursday, August 12, 2004 - link

    Nice to see asus get a award but unfourtanetly the word "prescott" mentioned in any sentence will probably scare away 80% of AT'ers.

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