Memory Stress Testing

Optimum tRAS

In past reviews, memory bandwidth tests established that a tRAS of 10 was optimal for the nForce3 chipset and a tRAS setting of 11 or 12 was generally best for nForce2. Since this was the first memory stress test of a production nForce4 board, 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 was measured from tRAS 5 to tRAS 11 to determine the best setting.

Memtest86 Bandwidth
DFI nForce4 with Athlon64 4000+
5 tRAS 2191
6 tRAS 2242
7 tRAS 2242
8 tRAS 2242
9 tRAS 2141
10 tRAS 2141
11 tRAS 2092

The best bandwidth was achieved in the 6 to 8 range with this combination of nForce4 and the 4000+, so a mid-value tRAS of 7 was chosen for all tests.

Memory Stress Tests

Our memory stress test measures the ability of the DFI to operate at its officially supported memory frequency (400MHz DDR), at the lowest memory timings that OCZ PC3200 Platinum Rev. 2 modules will support. All DIMMs used for stress testing were 512MB double-sided (or double-bank) memory. To make sure that memory performed properly in Dual-Channel mode, memory was only tested using either one dual-channel (2 DIMMs) or 2 dual-channels (4 DIMMs).

Stable DDR400 Timings - One Dual-Channel
(2/4 DIMMs populated)
Clock Speed: 200MHz
CAS Latency: 2
RAS to CAS Delay: 2T
RAS Precharge: 7T
Precharge Delay: 2T
Command Rate: 1T

Using two DIMMs in Dual-Channel 128-bit mode, the memory performed in all benchmarks at the fastest 2-2-2-7 timings, at default 2.6V voltage.

Tests with 4 DS DIMMs on an AMD Athlon 64 system are more demanding, since AMD specifies DDR333 for this combination. However, most AMD Athlon 64 motherboards combined with recent AMD processors (the memory controller is on the AMD CPU) have been able to handle 4 DIMMs at DDR400.

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

Tests with all four DIMM slots populated on the DFI nForce4 boards required a 2T Command Rate with 4 DS DIMMs in two dual channels. This is the pattern seen on other top-performing Socket 939 boards, but we hoped that higher voltage might allow us to eek out 4 DS DIMM 1T performance. However, additional voltage did not help and DDR400 with 4DS DIMMs still required a 2T Command Rate on the DFI nForce4 boards.


Overclocking: DFI nForce4 Test Setup
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  • xsilver - Sunday, February 6, 2005 - link

    Is there already performance benchmarks for ATI's SLI option?? -- it would hardly be surprising that it beats nvidia's solution as it is 6months if not a year after (I did read that they were using differing approaches to SLI) -- I was only stressing that if ATI were in the same position nvidia is in now, they would do the same thing of price gouging, stopping such easy mods etc...
    when ATI's solution comes out nvidia will respond with either lowering their price below ATI or developing their own next gen product -- and the cycle will continue || LATEST = GREATEST - usually :)
  • bob661 - Saturday, February 5, 2005 - link

    #89
    They probably wouldn't have bothered if there wasn't so much press about it.
  • PrinceGaz - Saturday, February 5, 2005 - link

    It's only a few tens of dollars difference between an Ultra and official SLI board, given how much you'd be spending on two high-end graphics-cards if you go SLI, why would you even risk saving a few dollars in the first place and sourcing the bridge afterwards?

    The only people who are probably bothered about the Ultra to SLI mod being disabled, are those would would never buy two 6800GTs (or better) anyway. Reviews elsewhere have shown a 6800GT outperforms the 6600GT SLI in almost every game, so using SLI for 6600GTs is stupid.

    DFI would be fools to allow the Ultra to SLI hack to be continued if as a second-tier mobo manufacturer they expect to continue nVidia supplying them with chipsets. Even considering selling the bridge to Ultra owners struck me as foolish in the extreme for them.

    Myself I'll probably get an SLI board even though I'll never use two graphics cards, just because the price difference is so small compared with the other components that go into the system, and a mobo with all the bells and whistles is always nice to have "just in case".

    nVidia have made a great chipset in the nForce4, le's not deprive them of the revenue they deserve by not buying SLI boards if that's what you intend to do, or getting a lower cost board if you don't. Everyone who knows they'll never want to use SLI benefits from the price differential which allows Ultra chipsets to be sold slightly cheaper.
  • Zebo - Saturday, February 5, 2005 - link

    word on the street is buy your ultra board before 2/20 if you want to use Wes' SLI discovery...still does'nt help you find a bridge..

    xsilver- Bullheads about to beat NF4 like a drum, hold your tounge. I don't blame nvidia but I also belive in the FREEDOM of mobo makers to do what they will with a chipset they purchased...not to be lorded over by nivida on the back end.
  • erios666 - Saturday, February 5, 2005 - link

    Well, that update freaked me out. Ultra-D on order. ZZF seems to be the cheapest that's in stock. I'm still hoping to be able to play my vids in a surround gaming mode 3840x1024. We'll hafta see.
  • Locut0s - Saturday, February 5, 2005 - link

    It's a disappointment that Nvidia has decided to making modding these boards harder but hardly a surprise. If anything it's surprising they didn't do this earlier.
  • bupkus - Saturday, February 5, 2005 - link

    Competition from ATI is the only answer to this price gouge. Do you remember back before AMD's Athlon when it was just Intel with AMD and Cyrix trailing far behind?
  • xsilver - Saturday, February 5, 2005 - link

    lol -- bullhead will also be bullshit if ATI were in the same position -- nvidia is losing $30 per modded chip -- they want to reduce the possibilities of this --- duh! -- other mods were not 100% guaranteed - eg. opening pipes etc. but this was --
  • Zebo - Saturday, February 5, 2005 - link

    The more I deal with nvidia scum (PVP on my $450 card anyone?) the more I think I'm waiting for bullhead (ati's chipset)..
  • CrystalBay - Saturday, February 5, 2005 - link

    Keep up the good work oldman :)

    Signed another oldman... :0

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