4 DS DIMMs at 1T: Memory Stress Testing

The DFI easily handles 2-2-2-7-1T timings at stock speed with 2 double-sided dimms, as do almost any of the current boards for AMD Socket 939 from NVIDIA, SiS, VIA, and ULi. However, what is truly unique is that the DFI LANParty UT RDX200 is the first board designed to run four double-sided 512MB or 1GB DIMMs at the fastest timings and a 1T Command Rate. In fact, AMD specifications tell us that this is impossible. To his credit, Oskar Wu and DFI found a way to accomplish the impossible.

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: 1T
*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.

With the ability to run 4 DS DIMMs at 1T, we had the opportunity to finally show the impact of a drop to a 2T Command Rate on performance.

First, for those skeptical that this is possible, we captured screens from the freeware A64 Tweaker and CPU-Z showing operation of 4 DIMMs at 1T.


Click to enlarge.

All the benchmarks below were run with an FX-57 processor and are not directly comparable to our standard benchmarks which use an AMD 4000+ CPU.

To clearly demonstrate the impact of the normal 2T drop in Command Rate on performance, we ran Aquamark3 benchmarks with 2 DIMMs at 1T, 4 DIMMs at 2T, and the new option of 4 DIMMs at 1T.

2 DIMMs at 1T is normally the fastest available option.

You can see that doubling the memory, but being forced to drop to 2T Command Rate, lowers the A3 scores by over 1,000 points.

The surprise, however, is the new DFI option of 4DS DIMMs at 1T. Not only is there no performance loss - the scores are 2,000 points higher than 4DSx2T - but 4DS DIMMs at 1T outperforms 2x1T by almost 1,000 points. This makes 4DS DIMMs at 1T in the DFI to be the new performance leader at stock speeds.

For those who are thinking that surely there's a catch, the answer is "yes, there is". 1T operation is only possible to a frequency of about DDR406, which basically limits it to stock speeds. Above that speed, you must run 4 DS DIMMs at 2T as you normally must. However, at or near stock speeds, the 1T option is a brilliant development that delivers better performance.

Overclocking: DFI LANParty UT RDX200 Test Setup
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  • JarredWalton - Tuesday, October 18, 2005 - link

    SATA2 actually only increases the bandwidth from 1.5Gbps to 3.0Gbps. Since sustained transfer rates are still maxing out at around 100MBps (0.8Gbps), and that's only with RAID-0 and two drives... well, SATA2 isn't a huge deal. I don't recall seeing whether the ATI chipset supports NCQ, which is of course in a similar boat.

    USB2.0 performance is only really important if you use an external HDD. Most flash cards and other USB2.0 devices don't come anywhere near 60MBps, as Anand's USB Flash Drive article showed. USB2.0 video devices might also have trouble, though - not sure what the throughput on those is. 150Mbps should be enough, really. Isn't 1080i only a 20Mbps stream? (Or is it 20MBps?)
    Reply
  • haelduksf - Wednesday, October 19, 2005 - link

    Err...that's what I meant, 3 Gbps, not 300Mbps. in either case, it's quite useless, and will be for the forseeable future. Reply
  • erinlegault - Tuesday, October 18, 2005 - link

    I would have been nice if DFI would have used the ULI southbridge. Maybe DFI will include the ULI M1575 for the DFI LANParty UT RDX200 Expert motherboard (that's if they do the same as they've done with the NF4 board). Reply
  • DigitalFreak - Tuesday, October 18, 2005 - link

    Anyone else think this board is a bit lacking feature wise for the $230 asking price? If you REALLY want Crossfire, then you'll need this board. Otherwise, the Nforce4 seems to be the better choice. I just can't believe that DFI is asking so much $$$ for this! Reply
  • mongoosesRawesome - Tuesday, October 18, 2005 - link

    price will likely come down pretty quickly. remember how much the nforce 4 sli boards were when they came out?

    I've also heard rumors that DFI is going to release a new board with an updated southbridge in a few weeks.
    Reply
  • bob661 - Tuesday, October 18, 2005 - link

    quote:

    price will likely come down pretty quickly.
    Only if people buy these things otherwise there would be no reason to lower prices.
    Reply
  • coomar - Tuesday, October 18, 2005 - link

    226-2-2-2-7-2T is going to be faster than 206-2-2-2-7-1T

    vdimm and vcore voltage choices were very impressive

    how good is azalia compared to good soundcards/ decoders?
    Reply
  • muffin - Tuesday, October 18, 2005 - link

    DFI was not the first! EQS have had a board on sale at overclock.co.uk for a couple of weeks now. Its the same as the (as yet unreleased) Sapphire board, made by the same people.

    Linky: http://www.overclock.co.uk/customer/product.php?pr...">http://www.overclock.co.uk/customer/product.php?pr...

    Its been on sale for a while guys, pay attention. Theres an Inquirer story about it too :/
    Reply
  • erinlegault - Tuesday, October 18, 2005 - link

    There is data for x850XT missing in the Half-Life 2, Wolfenstein, Aquamark and UT2004 Reply
  • Wesley Fink - Tuesday, October 18, 2005 - link

    Due to time constraints we did not run a full set of Crossfire benchmarks. We were mainly trying to confirm Crossfire worked as it should on the DFI. We therefore ran those benches where more powerful video makes a difference and left out those where the video power makes little difference. You can find a full suite of Crossfire, 7800GTX, and other graphics benchches in our Crossfire Graphics launch reviews under the Video tab at the top of the page.

    We did intend to run Half Life 2 but our benchmarks no longer work with the new build Steam forces on you. We are in the process of updating the HL2 benchmark unless some of you tech wizards know of an HL2 benchmark that will definitely work with the new HL2 version.
    Reply

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