Abit AV8: Overclocking and Stress Testing

FSB Overclocking Results


Front Side Bus Overclocking Testbed
Processor: Athlon 64 FX53 Socket 939
2.4GHz
CPU Voltage: 1.5V (default)
Cooling: Thermaltake Silent Boost K8
Power Supply: Antec TruePower 430W
Maximum OC:
(Standard Ratios)
203 x13
2642MHz (+10.1%)
Maximum FSB:
(Lower Ratio)
280x9 (2520) at 1:1 Memory

Our FX53 easily achieved the next speed level of 2.6GHz on the Abit AV8. This will likely be the speed rating of the FX55, which will appear later this year. The best proof that the Abit has a working PCI/AGP lock can be seen in the fact that we were able to run DDR550 memory at 280x9 on the Abit. To achieve this overclock level, we needed to reduce the base HyperTransport frequency to 800. The AV8 could reach 300 CPU frequency at lower memory ratios and a 8 multiplier. We did find that the Abit did not really like an HT setting lower than 800, so we were limited to 300 as the maximum usable FSB.

Memory Stress Test Results:

The memory stress test measures the ability of the Abit AV8 to operate at its officially supported memory frequency (400MHz DDR), at the best performing memory timings that our Mushkin PC3500 Level 2 or OCZ PC3500 Platinum Ltd Modules will support. Memory stress testing was conducted by running RAM at 400MHz with 2 DIMM slots operating in Dual-Channel mode. The memory configuration of the Abit is a little unusual in that the first 2 DIMM slots represent a Dual-Channel. On most Dual-Channel motherboards, slots 1 and 3 are the first Dual Channel.

Stable DDR400 Timings - 2 DIMMs
(2/4 DIMMs - 1 Dual-Channel Bank)
Clock Speed: 200MHz
Timing Mode: N/A
CAS Latency: 2.0
Bank Interleave: N/A
RAS to CAS Delay: 2T
RAS Precharge: 10T*
Precharge Delay: 2T
Command Rate: 1T
*Several memory tests have shown that memory performs fastest on the nVidia nForce and VIA K8T800 chipsets at a TRas (RAS Precharge) setting in the 9 to 13 range. We ran our own Memory Bandwidth tests with memtest86, with TRas settings from 5 to 15 at a wide range of different memory speeds. The best bandwidth was consistently at 9 to 11 at every speed, with TRas 10 always in the best range at every speed. The memory bandwidth improvement at TRas 10 was only 2% to 4% over TRas 5 and 6 depending on the speed, but the performance advantage was consistent across all tests. Since best performance was achieved at 2-2-2-10 timings, all Athlon 64 benchmarks were run at a TRas setting of 10.

The Abit KV8 PRO was completely stable with 2 DIMMs in Dual-Channel at the best performing settings of 2-2-2-10, at 2.6V default voltage. It should be noted that the BH5 memory modules that we used for testing are no longer available for purchase, but we have not yet established our standard memory for future testing. We will be using a new standard memory in future motherboard tests.

As we first found in our latest Socket 754 roundup, the Command Rate is very important for top performance on a VIA chipset motherboard. The best performance is at a Command Rate of 1T, and the Abit AV8 was completely stable at a 1T setting with 2 DIMMs. Standard memory bandwidth measured with SiSoft Sandra 2004 SP2 shows a 6000 MB/s bandwidth with 1T Command Rate compared to a 5000 MB/s bandwidth with a 2T setting. While we could not set "Bank Interleave" in the BIOS, Sandra 2004 reported that a 2-way Bank Interleave was being used by the memory controller. With an on-CPU memory controller with Athlon 64, this is not as important a setting as it is on with chipset-based memory controllers.

Filling all four available memory slots is more strenuous on the memory subsystem than testing 2 DIMMs on a motherboard.

Stable DDR400 Timings - 4 DIMMs
(4/4 DIMMs - 2 Dual-Channel Banks)
Clock Speed: 200MHz
Timing Mode: N/A
CAS Latency: 2.0
Bank Interleave: N/A
RAS to CAS Delay: 2T
RAS Precharge: 10T*
Precharge Delay: 2T
Command Rate: 2T

The Abit AV8 was able to run with all 4 DIMM slots at the same aggressive 2-2-2-10 settings used for 2 DIMMs. However, Command Rate must be reduced to 2T when filling both Dual Channels.

During the course of testing for the 939 roundup, we experienced a failure of our FX53 processor. AMD was very gracious in quickly providing a replacement so testing could continue. The FX53 failure is probably rare, but the way that the CPU failed provided some insight into the Athlon 64 on-board memory controller. We first noticed new boards requiring much slower timings for memory; in most cases CAS 2.5 was required where CAS 2 had worked previously. This appeared to be motherboard differences, so we continued testing. Later, the FX53 failed. The replacement first went into a board where CAS 2.5 or 3 had been required, and now the same board performed fine at CAS 2 memory timings. Our point here is that the problem was the on-CPU memory controller failing and not the motherboard. The on-CPU memory controller is wonderful for reducing latency, but, unlike the past, memory problems may also be related to the CPU and not just the motherboard.

Abit AV8: Features and Layout Asus A8V Deluxe: Features and Layout
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  • thebluesgnr - Tuesday, July 20, 2004 - link

    "Our FX53 topped out at about 3.59 GHz on the ECS KV2, which is slightly below the 3.6+ achieved on the top 939 boards."

    Is this ECS a P4 board? :P

    This was a great article. I agree with other readers, CnQ should definately have been tested, as well as audio and IDE subsystems.

    btw Wesley, will there be reviews of KT880 socket A mobos in the future?

  • TrogdorJW - Tuesday, July 20, 2004 - link

    Just a few comments. It's a little (*little* mind you) unfair to compare FX-53 to P4 560, given the price advantage of the P4. Then again, comparing it to the P4EE is a little unfair in the other direction. It might have been nice to include one or two other systems in the benchmarks, though, like a 3400+. Sure, we can cross-reference other articles, but if you have all the data already it would be a lot cleaner. I'm especially interested in seeing AutoGK benchmarks with the "lesser" Athlon 64 processors (3500+ and 3400+ would be good, or maybe even 3200+ - not everyone has $400+ to spend on a CPU!)

    Of course, while it might be less fair to Intel, I would like to get AutoGK numbers using Xvid as well. That's how I use it, as I feel the quality is a little better than DivX. Oh, and while you state that you used 2-pass encoding, what was the target resolution? 640x360, or 720x408, or something else? And did you specify a target size, or was it on unlimited quality? All those are important questions, I think.

    One final request: I truly appreciate the memory stress testing benchmarks. However, I would like it taken a little further. All of the boards claim that they can support up to 4 GB of RAM. I would love to see some tests showing this configuration. After all, 64-bits is really about breaking that memory barrier. Even if the boards need to run 4x1GB at DDR266 or DDR333, it would be good to know. (Too bad there simply aren't many good 1 GB DIMMs available yet.)
  • Wesley Fink - Tuesday, July 20, 2004 - link

    #14 & #20 - Perhaps tests with the X800 XT on nF3 compared to the 6800 Ultra will at least shed a little light on where the efficiencies lie - in the nF3/nV Video combo or in the nF3 itself.

    #16 - We will make an effort to talk a bit more about Cool'n'Quiet in individual board reviews, but in a roundup like this it is difficult to explore that level of detail, and still hold the article length to anthing you might want to read. We try to do more with features in individual reviews.

    #19 - We report the full range of vCore in our board charts for people like you who are interested in umdervolting. If you notice some boards begin vCore at default, while others make a wide undervolt range available as well as overvolt. We try to report this range as accurately as possible for this reason.
  • Pete - Tuesday, July 20, 2004 - link

    Wesley, very interesting numbers. Halo is supposedly limited by some inefficient DX9 layers/commands, so I at first thought maybe nV had somehow optimized or bypassed some DX9 calls. The office and Content Creation benchmarks advantage is more puzzling, though. Could nV's performance edge be the result of some intelligent caching or either the HD or the CPU?

    Testing an X800 for reference is a good idea for Halo. Just be sure to retest the office and Content Creation suites, too, as the performance boost there is equally curious, IMO.

    I found one typo, on the system specs page. It's Wolfenstein: Enemy Territory, not Wolfenstein: Enemy Within. :)
  • JKing76 - Tuesday, July 20, 2004 - link

    Sure there's Cool'n'Quiet, but how about adding manual undervolting capabilities to the review? A lot of mobos only allow upping the vcore, but undervolting is a great tool for creating a truely cool and quiet system without losing performance.
  • XRaider - Tuesday, July 20, 2004 - link

    Love that FX53 and the MSI K8N Neo2 together. Sure is purdy nice!! ;) But must...hold...out...until...price..drops...some..more.. ;o)
    Great article BTW!
  • XRaider - Tuesday, July 20, 2004 - link

    Love that FX53 and the MSI K8N Neo2 together. Sure is purdy nice!! ;) But must...hold...out...until...price..drops...some..more.. ;o)
    Great article BTW!
  • jojo4u - Tuesday, July 20, 2004 - link

    I miss information about Cool'n'Quiet. It's a shame that anandtech.com only is insterested in overclocking and speed.
  • esSJae - Tuesday, July 20, 2004 - link

    Nice, another article touting the non-existent MSI K8N Neo2.

    Sure, you can go to MSI's Taiwan site and download the manual and BIOS, but doesn't seem to be much point in that.
  • DAPUNISHER - Tuesday, July 20, 2004 - link

    "We never expected the nVidia nForce3-250 Ultra to be a better performer in Winstone benchmarks than the VIA K8T800 PRO. However, both the nF3-250 boards are outperforming the VIA boards by a significant percentage. Since the nVidia 6800 Ultra video card was used for all benchmarking in the roundup, we plan to verify these results with an ATI X800 XT as soon as that board is available to the Motherboard Lab for testing"

    Is this to determine if it's a result of forceware opts that is responsible for the difference observed?

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