Optimum tRAS

In past reviews, memory bandwidth tests established that a tRAS setting of 11 or 12 was generally best for nForce2, a tRAS of 10 was optimal for the nForce3 chipset, a tRAS of 7 was optimal for the nForce4/ATI RD480/ULi M1697 chipsets, and a tRAS of 10 produced the best bandwidth on the ULi 1695.

Since this is our first review of a board with the new ATI RD580 chipset, tRAS timings were first tested with memtest86, a free diagnostic program with its own boot OS that will boot from either a floppy disk or optical disk. Bandwidth of OCZ PC3200 Platinum Rev. 2, based on Samsung TCCD chips, was measured from tRAS 5 to tRAS 15 to determine the best setting.

Memtest86 Bandwidth
Asus A8R32-MVP with Athlon 64 4000+
5 tRAS 1879
6 tRAS 1879
7 tRAS 1999
8 tRAS 2043
9 tRAS 1999
10 tRAS 1958
11 tRAS 1958
12 tRAS 1879
13 tRAS 1870
14 tRAS 1843
15 tRAS 1807

The tRAS setting that produced the highest memory bandwidth with the ATI RD580 chipset was 8. The tRas 8 setting was used for all memory testing on the Asus A8R32-MVP Deluxe.

Memory Stress Testing

The Asus A8R32-MVP easily handles 2-2-2-8-1T timings at stock speed. The default setting for Command Rate in the Asus BIOS is 1T, which makes it much easier to assure that the A8R32-MVP consistently delivers top performance than the 2T default seen in the earlier A8R-MVP. We are pleased that Asus decided to implement the more sensible 1T timings in the update to the A8R-MVP.

Running four double-sided 512MB or 1GB DIMMs is much more demanding than running two DS DIMMs, and Asus did not have any special 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. This really should not be a surprise, since the DIMM timing is primarily a function of the memory controller on the AMD processor. With 4 DIMMs, the A8R32-MVP remained stable with the same aggressive 2-2-2-8 timings that worked best 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: 8T*
Precharge Delay: 2T
Command Rate: 2T
*8T was determined by MemTest86 benchmarks to deliver the widest bandwidth with the ATI RD580 chipset. While the board would operate at tRAS of 5T or lower all benchmarks were run at 8T.

Overclocking: Asus A8R32-MVP Test Setup
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  • superkdogg - Wednesday, March 1, 2006 - link

    If you had been working for half the time you have been whining on every forum you can find, you could have bought two SLI-Experts or whatever motherboard you think has no problems.

    Dude, get over it. The A8R was not exactly as reviewed here. Is that disappointing? Yep. Unfair? Maybe. Fact is, anybody who bought it for the "serious overclocking" that you're referencing would do a vMod and get on with it. I have two A8R's. One is dead because I was stupid and tried a vMod. My soldering needs work. I bought a second one on refurb for $75 because I realized that in the best case, that vMod might get me another 150 MHz. You know what else would get me 150 MHz? Dusting off a Pentium Pro in my basement. I could also get the 2% benefit that 1T timing would give me from chance, since most 'marks are + or - 2-3%.

    I was burned by the same problem you were. I have learned to live with it and am currently happily running 300x9 with ram @ 2.5-4-4-9, 2T (166/200). That's not bad for standard blue heatspreader Patriot that runs about $80 per gig.
  • DigitalFreak - Wednesday, March 1, 2006 - link

    Omid, is that you?
  • yacoub - Sunday, February 19, 2006 - link

    Should have run the 3DMark benches with the 7800GTX like all the other boards so at least we could see if the board itself (the object of review) offered any particular performance gain or loss. :[
  • yacoub - Sunday, February 19, 2006 - link

    oic now, thanks. :)

    green bars. tricksy hobbitses!
  • Missing Ghost - Sunday, February 19, 2006 - link

    I am unhappy with the pictures of the board included in this review. I can't see anything on them because they are too dark. I couldn't even tell if they were a firewire port on the back.
  • Wesley Fink - Wednesday, March 1, 2006 - link

    The pictures are not overly dark on several monitors we tried in reading the review. I'm sorry I don't have advice in that area.

    As stated in the review, both Firewire ports are on an accesory bracket included with the motherboard. The bracket will fit in an empty slot or can be routed to case firewire ports.
  • Googer - Sunday, February 19, 2006 - link

    What Phase Power is this motherboard using? 2,3,4,8,24?
  • Beenthere - Sunday, February 19, 2006 - link

    Any properly designed 3-phase or greater CPU vcore circuit that complies with AMD's VRM64/T specs will work just fine. If however a mfg. delivers a poor circuit design or uses inferior MOSFETS, caps, etc., then you experience Vcore instability which causes all kinds of operational Hell. More phases just lowers the ripple and spreads the load across more MOSFETS.
  • Beenthere - Sunday, February 19, 2006 - link

    BTW, if you check the A8R-MVP, the A8N series and the Asus P5GL-MX you'll see that all of these mobos have been confirmed to have vcore instability problems when tested at the mobo with a DVM or scope. Asus seems to have some significant mobo engineering issues they can't resolve... and that are not present on other brands of mobos using the same chipsets.
  • Ecmaster76 - Sunday, February 19, 2006 - link

    Do you work for DFI or Abit or something? This is the third site where I have ran into you flaming Asus constantly!


    (where did I put that troll repellant)

    Seriously, link some proof of said Vcore instability. Show me scope printouts of the Vcore lines (and the 12v rails that were used to drive it)

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