Overclocking

Asus A8R-MVP Overclocking Testbed
Processor: Athlon 64 4000+
(2.4GHz, 1MB Cache)
CPU Voltage: 1.45V (default 1.40V)
Cooling: Thermaltake Silent Boost K8 Heatsink/Fan
Power Supply: OCZ Power Stream 520W
Memory: OCZ PC3200* Platinum Rev. 2
(Samsung TCCD Memory Chips)
*The current equivalent OCZ memory is OCZ PC4800
Hard Drive: Seagate 120GB 7200RPM SATA 8MB Cache
Maximum OC:
(Standard Ratio)
246x12 (4x HT, 2.5-3-3-7)
2952MHz (+23%)
Maximum FSB:
(Lower Ratio)
325 x 9 (3x HT, 2T*, 3-4-3-8)
(2925MHz, 2 DIMMs in DC mode)
(+62.5% Bus Overclock)

Screen captures on the first page have already announced that the Asus A8R-MVP has set new overclocking records in our testing. We actually found 330 to be stable in memtest86 and booted into Windows at a little more than 330 with memory set to a DDR400 starting point. However, Windows was not completely stable at 330 and required a slight lowering to 325 (DDR650). The 325 setting was completely stable, ran our benchmarks, and ran for more than 2 days on just air cooling.

Our first efforts at overclocking the A8R-MVP ran into a road block at just over 260. We have found some Asus boards in the past that did not like overclocks to be immediately set to high values, so we started again at 250. By going up just 5 to 10FSB at a time, we were able to reach 325. Since we had no idea that we would reach such a high OC on this mainstream board, we have screen captures at every 5MHz from about 270 to 330. Our advice to overclockers on this board is to move the overclock up slowly.

*UPDATE: After further testing we have concluded that the A8R-MVP handles 1T timings only to about 260-265. Above 260-265 you will need 2T timings to reach 325 or so clock frequency. We ran into a wall at 260 and apparently the BIOS reset. The default is 2T and we didn't catch the Command Rate reset. This board uses very aggressive timings, and the 2T memory bandwidth was so fast we did not realize the board was actually running at 2T. This does not change the fact that 325 at 2T is an outstanding overclock, but it is achieved at 2T timings, and not at 1T as originally reported.

Those who don't understand overclocking or who don't want to bother will find extensive automatic overclocking options in the Asus BIOS. This allows you to set an overclock and have the board adjust the related settings. These work well for modest overclocking, but they will not allow the extreme results achieved manually on the Asus A8R-MVP.

Memory Stress Testing

The Asus A8R-MVP easily handles 2-2-2-7-1T timings at stock speed, as do almost any of the current boards for AMD Socket 939 from NVIDIA, SiS, VIA, ATI, and ULi. However, the default setting for Command Rate in the Asus BIOS is 2T, and you need to manually set Command Rate to 1T for best performance with 2 DIMMs in Dual Channel mode. Asus tells us that this was done to accommodate some memory manufacturers that had asked for a default 2T Command Rate for maximum compatibility with their memory. Once set, we had no issues using 1T command Rate with any memory that we tested.

Running four double-sided 512MB or 1GB DIMMs is much more demanding than running two DS DIMMs, and Asus did not have any extra magic here. Like every board that we have tested except the DFI RDX200, we needed to drop the Command Rate to 2T with 4 DS DIMMs. With 4 DIMMs, the A8R-MVP remained stable with the same aggressive 2-2-2-7 timings used for two DS DIMMs.

Stable DDR400 Timings - 4 DIMMs
(4/4 DIMMs populated)
Clock Speed: 200MHz
CAS Latency: 2.0
RAS to CAS Delay: 2T
RAS Precharge: 7T*
Precharge Delay: 2T
Command Rate: 2T
*7T was determined by MemTest86 benchmarks to deliver the widest bandwidth with the ATI Rx480/482 chipset. While the board would operate at tRAS of 5T or lower, all benchmarks were run at 7T.
Basic Features: Asus A8R-MVP Test Setup
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  • EnlightenedOne - Thursday, December 8, 2005 - link

    Hey Wesley, Great Review!

    I was wondering a few things with this motherboard and the setup.
    First, do you think the clawhammer 4000+ would overclock better than the Diego?
    What voltage are you feeding your ram to reach such a high frequency?
    Do you suggest using the 246 x 12 or the 325 x 9 set up for games?
    Finally, what voltage are you feeding the PCIe slot? Also, why haven't you upped the voltage to your cpu core to maintain stability and go beyond 2 days? :)
  • Zebo - Thursday, November 24, 2005 - link

    Great having spread out memory slots. I found many A64 boards stack the dual channel sticks so close they are actually touching between sticks fi you have heat spreaders on there and they can't cool.

    Price!! I sure miss top of the line boards in the $100 range (Abit NF7-S Abit IS7 etc)granted this new era has high power requirements and thus a beffier boards but no excuse for these $200+ mobos floating around for enthusiants. nV and Intel must be charging crazy high prices for thier newer chipsets.. Thanks ATI.

    Legacy support - My printer won't work with full features on USB alone... needs Parallel cable for full control which my DFI does'nt have.

    - overclocking potential as Mr. Fink illustrated.

    - full features including Fast disk benches and great on-board audio (FWIW).

    - Passive cooled mobo design - How many of you hate those whinny 40mm/60mm fans that come on mobos? When they work that is.

    Asus really needs to adopt Black though for thier entire lineup unless it goes in an OEM build.. I mean that yellow traces and green board is so 1990's.:(
  • Live - Thursday, November 24, 2005 - link

    s.
    quote:

    - Passive cooled mobo design - How many of you hate those whinny 40mm/60mm fans that come on mobos? When they work that is.


    I couldn’t agree more. Those small fans are highly unreliable and very noisy. And with today’s heat pipe tech there is no reason to not go passive even on the high end boards. ASUS seems to be leading the pack on this. To bad they cant/won’t go all out in their bios. DFI in particular have them beat in bios all the time.
  • Sxotty - Wednesday, November 23, 2005 - link

    quote:

    There is always the possibility that this one is unique. But based on the Asus expectations being set very low for this board, and the genuine surprise that Asus expressed when we reported our results, I would venture to say that what we found is not a fluke.


    That is really not a very thoughtful way to look at it.

    If ASUS was "surprised" by your results that would argue they are atypical not typical. It is not as though they never tested the motherboard to see if it worked. If you ever find an engineer surprised by your results than you should assume that they do not represent what the acerage was expected to be. Perhaps it is a wonderful overclocker, but that is evidence that it is not. Perhaps the engineer that was so "promising" really did an excellent job and the other people you spoke with just did not happen to know the test results.

  • Wesley Fink - Wednesday, November 23, 2005 - link

    I can only report what I actually find, and we can both "suppose" all day long. Time will prove whether these overclocking results are typical or atypical.

    As i said in a comment above: "Asus does extensive overclocking tests on their top-line boards aimed at that market. They generally know how they will perform in overclocking. They do more modest tests on mainstream boards. It is my opinion it never occured to Asus that the A8R-MVP might be a monster overclocker until I reported my results back to them."

    I have worked closely with the Asus Engineering team in Taiwan on several Enthusiast board projects, and since my initial results were shared with them after the second BIOS they have not given me any reason to expect that they are not typical for this board. As I said in the Final Words: "We would feel much more comfortable in our praise of the A8R-MVP if we had an opportunity to prove similar overclocking on another five boards pulled at random from retail shelves."
  • Zebo - Thursday, November 24, 2005 - link

    ATI “Certified Motherboard?"?
  • afrost - Wednesday, November 23, 2005 - link

    I can't wait to get my hands on this board.....I have been waiting for a solid passively cooled board like this for a long time.

    The HD audio is a very nice bonus.
  • Wesley Fink - Wednesday, November 23, 2005 - link

    We did additional tests on the Asus A8N32-SLI Deluxe Dual x16 this morning, running at our standard 1280x1024 with AA and AF turned off, with 81.87 drivers. We have added A8N32-SLI benchmarks to F.E.A.R., SC-CT, Quake 4, Doom 3, Far Cry, and Wolfenstein - Enemy Territory.

    The added benchmarks do not really change any of our conclusions. As you can see, the Asus A8R-MVP is very competetive with the top-line A8N32-SLI Deluxe.
  • nvidia4ever - Wednesday, November 23, 2005 - link

    Thanks for the updates. It really does look like there is another performance choice now for AMD systems. I still would find it interesting to see how a x1800xt performs on ATIs own chipset.
  • Duplex - Wednesday, November 23, 2005 - link

    The only thing me and my friends missed is overclockingresults
    for the memory with tight timings like 1T 2-2-2-5 or 2-2-2-7.
    The 1T overclocking performance for Asus and Abit has yet been very poor,
    with tigh timings even worse. Abit has added higher vdimm options but it
    hasn´t helped much. Has this changed with this Asus-Ati-mb or is dfi nf4
    still my only option for pc-builds? 230/240/250/260 (/270) MHz???

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