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. The ASUS A8R32-MVP review established that a tRAS setting of 8 produced the highest bandwidth on the RD580 chipset. That review describes the test procedure and the shows the results that show 8 to be the best tRAS setting. We used the tRAS 8 setting for all benchmarking.

Memory Stress Testing

The DFI CFX3200-DR easily handles 2-2-2-8-1T timings at stock speed. The default setting for Command Rate is 1T, but it is a little more difficult to determine how to force 1T for higher overclocks. The setting to control Command Rate is under "Genie BIOS Setting", "DRAM Configuration", "Command per Clock (CPC)". Instead of simple Auto, 1T, 2T settings, the options are Auto, Enable, Disable. After a bit of testing we figured out that ENABLE is 1T and DISABLE is 2T. Auto normally returns 1T, but you can force 1T with the ENABLE setting if you wish.

Running four double-sided 512MB or 1GB DIMMs is much more demanding than running two DS DIMMs, and like almost every board we have tested the Command Rate needed to drop 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 DFI CFX3200-DR 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
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 Test Setup
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  • rqle - Monday, May 8, 2006 - link

    "...breathlessly waiting for DFI's AM2 and Conroe motherboards."
    Great board, but not sure where this new mainboard will fit in since AM2 is coming, many can opt for the nforce expert if they need a board before AM2.

    hoping AM2 version is in the works and will be release soon as well.
  • electronox - Monday, May 8, 2006 - link

    *sigh*

    as far as gaming benchmarks go, what we really need to learn to do is to focus on the lowest framerates rather than the highest framerates (or even the average framerate). fink, anand, and co., you guys offer a progressive tech-journalism and no doubt have thought about what FPS performance really means.

    in its most important application, FPS performance means the ability to convey a smooth, fluid visual experience without noticeable dips or jerks in motion. sadly, with the way things are marketed now, the overall fluidity of gaming is sacrificed to reach those peak framerates we all obsess about in our benchmarking suites.

    as a long time gamer and enthusiast-sector consumer, i wish such high profile websites as yours would pay more attention to the worst parts of FPS gaming - the parts of the game where the intensity of in-game content is notched up, but often our video settings must be turned down in order to prevent epileptic siezures. such media attention might, in turn, lead industry developers to optimize their drivers for this exceedingly common problem which, in my opinon, is just as easily quantifiable and ever bit as important as average FPS performance.

    my thoughts, electronox.
  • Dfere - Monday, May 8, 2006 - link

    I have to agree. I make good money, but I no longer have the time to play with bleeding edge components and do modding. I know this is an enthusiast site, but at least for me , and I think a large amount of readers, an analysis of the max you might get out of a bleeding edge system is not all the value your site brings. A lot of posts by the readers show they have mid range systems. Thus I can only agree that an analysis of the FPS "issues" described above with a mid range system would help readers identify what would best go with their current system, not just a top of the line upgrade. I know your testing tries to determine , for example, CPU limits or GPU limits...... but it really only does so on bleeding edge systems..... and these comments were already mirrored in the latest AGP vid card releases......(why compare a new AGP card with new processor when most AGP owners have 754 systems.... etc)
  • JarredWalton - Monday, May 8, 2006 - link

    I think it all depends on what game you're talking about, and how the impact is felt in the fluidity of the FPS score. These days, the vast majority of first-person shooters have a pretty consistent FPS, at least in normal gaming. In benchmarks, you're often stressing the games in a somewhat unrealistic sense -- playing back a demo at three or four times the speed at which it was recorded. Why does that matter? Well, depending on the game engine, loading of data can occur in the background without actually slowing performance down much, if at all. In a time demo, you don't generally get that capability, since everything moves much faster.

    There are several other difficulties with providing minimum frame rates. Many games don't report instantaneous frames per second and only provide you with the average score. (Doom 3, Quake 4, Call of Duty 2, Half-Life 2, Day of Defeat: Source all generate scores automatically, but don't provide minimum and maximum frame rates.) If we notice inconsistent frame rates, we do generally comment on the fact. About the only game where I still notice inconsistent frame rates is Battlefield 2 with only 1GB of RAM -- at least on a system of this performance level. (I suppose I should throw in Oblivion as well.)

    Sure, we could use tools like FRAPS together more detailed information, but given that there's a limited amount of time to get reviews done, would you rather have fewer games with more detailed stats, or more games with average frame rates? Realistically, we can't do both on every single article. Our motherboard reviews try to stay consistent within motherboards, our processor reviews do the same within CPU articles, and the same goes with graphics cards and other areas. If we have an article where we look at results from one specific game, we will often use that to establish a baseline metric for performance, and readers that are interested in knowing more about the benchmark can refer back to that game article.

    Average frame rates are not the be-all, end-all of performance. However, neither are they useless or meaningless. we run into similar problems if we report minimum frame rates -- did the minimum frame rate occur once, twice, frequently? As long as people understand that average frame rates are an abstraction representing several layers of performance, than they can glean meaning from the results. You almost never get higher average frame rates with lower minimum frame rates, or conversely lower average frame rates with higher minimum frame rates -- not in a single game. In the vast majority of benchmarks, an increase in average frame rate of 10 FPS usually means that minimum frame rates have gone up as well -- maybe not 10 FPS, but probably 7 or 8 FPS at least.

    In the end, without turning every article into a treatise on statistics, not to mention drastically increasing the complexity of our graphs, it's generally better to stick with average frame rates. Individual articles may look at minimum and maximum frame rates as well, but doing that for every single article that uses a benchmark rapidly consumes all of our time. Are we being lazy, or merely efficient? I'd like to think it's the latter. :-)

    Regards,
    Jarred Walton
    Hardware Editor
    AnandTech.com
  • OvErHeAtInG - Monday, May 8, 2006 - link

    Good answer :) Also I think that minimum framerates (while very important in gameplay) are much more impacted by the videocard used. With a motherboard review, we're much more concerned with overall performance, which is exactly what you gave us with the avg. framerate numbers...

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