Abit AV8: Overclocking and Stress Testing

FSB Overclocking Results

Front Side Bus Overclocking Testbed
Processor: Athlon 64 FX53 Socket 939
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


View All Comments

  • harsaphes - Sunday, October 10, 2004 - link

    just set up my a8v board. no go on firewire, will not see ipod or external firewire drive. any idea?...bad board maybe? Reply
  • kd4yum - Thursday, August 05, 2004 - link

  • Fender - Wednesday, August 04, 2004 - link

    The first words in this review confirm that you should never buy a VIA product before they revised it! (KT266 to 400 saga anyone?)
    Also, it's oddly that Hyperions used here are 8 months old...
    It could be interesting if you include, in your tests, any possible issue concerning OS installation or updating drivers (from the CD included in the box to the updated drivers from the manufacturer's site) because this is what happens to most buyers out there. Remember that you're testing a 64bit CPU with a 32bit OS, and drivers development will be a further support insurance.
  • Wesley Fink - Tuesday, August 03, 2004 - link

    #79 - Page 13 is corrected. That error slipped past 3 proofreaders. Thank you for alerting us. Reply
  • Sidewinder0010 - Tuesday, August 03, 2004 - link

    the k8t neo2 overclocking page has a typo that was throwing me off
    "much lower than the 290 on the K8T Neo2"
    That should be changed to k8n neo2
  • Compddd - Friday, July 30, 2004 - link

    Wesley, did Asus say when the A8V Rev 2.0 will be hitting Retail Stores like Fry's, Best Buy, etc? Reply
  • thebluesgnr - Friday, July 30, 2004 - link

    How does the lower bandwidth (4900Mb/s) affect real world performance?

    One more thing, perhaps the MSI K8T Neo2 Platinum references should be changed to MSI K8T Neo2-FIR? That's the name of this board on MSI's site, there's no mention of it being a Platinum board. And here's a link of all the boards in the Platinum series: http://www.msicomputer.com/pressrelease/platinum.a...

    Off-Topic: Wesley, will there be reviews on AnandTech of Socket A mobos based on the nForce2 Ultra 400Gb and VIA KT880 chipsets? They offer the exact same features of the mobos on this roundup, and with the new Semprons and the good XP-Mobiles I suspect a lot of your readers are still interested in this socket.
    Sorry for the off-topic.
  • Wesley Fink - Friday, July 30, 2004 - link

    #75 - You are confusing boards as MSI had TWO boards in the roundup. We had no problems at all with the first or second K8N Neo2 (based on nForce3 Ultra) we tested, and that is the board that received the Gold Editors Choice. The MSI K8T Neo2, based on the VIA K8T800 PRO, was the problem board and we definitely did NOT give the K8T Neo2 an award.

    #74 - On page 5 we talk about the memory bandwidth differences in 1T and 2T command rates: "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." This is also mentioned on page 11: "While a full memory comparison of the nVidia and VIA chipsets is beyond the scope of this roundup, we did run several SiSoft Sandra 2004 SP2 runs of the memory test module. At default settings, and the aggressive 2-2-2-10 timings on the FX53, the nF3-250 Ultra showed memory bandwidth in the 6100 range for FPU and Float. The same test on the VIA K8T800 PRO boards showed memory bandwidth in the 6000 range. Performance of both chipsets at the 1T setting was very similar. 2T Command Rates, with everything else the same, generated bandwidths of 4900 to 5000Mb/second."

  • Z80 - Friday, July 30, 2004 - link

    Considering your statement "Our concern is based on the fact that we went through 3 K8T Neo2 boards before we got one that really worked" I'm surprised that you went ahead and gave the MSI board your gold award. I see that MSI is being sued for intentionally using capacitors that were made with an improperly-formulated electrolyte solution. My personal experience with MSI quality assurance was never good at least back in the day it wan't but maybe they have changed like you say OCZ has? I'll stick with Asus and Abit, thank you. Reply
  • SignalPST - Friday, July 30, 2004 - link

    quote from the article:
    "We even found that all six of the tested motherboards performed at the fastest timings available and a 2T Command Rate with 4 DIMMs on board, so even that is a non-issue."

    Does that mean that if 4 sticks of ram are installed, there won't be a performance hit and it will work just as fast as 2 sticks installed?

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