Investigations into Athlon X2 Overclocking
by Jarred Walton on December 21, 2005 12:00 PM EST- Posted in
- CPUs
RAM Ratios
We mentioned before that additional RAM ratios would be helpful, and higher end motherboards like the DFI LanParty series often provide them. The Infinity board is limited to DDR400, DDR333, DDR300, DDR266, and DDR200 – at least with the current BIOS. In reality, these are not exact speeds but rather the maximum speed at which the RAM will run with the CPU at stock speed. RAM speed on AMD K8 systems is derived from the CPU speed. With our X2 3800+, “DDR400” results in a CPU/10 RAM divider. 2000/10 = 200 MHz. The 10X multiplier actually makes for very nice RAM speeds, as CPU/12 = 166.7 MHz, CPU/15 = 133.3 MHz, and CPU/20 = 100 MHz. The DDR300 setting is the only one that’s off, as 2000/14 = 143 MHz.
With other motherboards, you may get several additional memory ratios, including those above DDR-400. This provides additional options for reaching maximum performance. In the end, the memory ratios come down to one point. All things being equal (i.e. with identical timings), higher bandwidth will be faster. It may not be a lot faster, but it could be a difference of several percent.
Was that a third strike against the Infinity motherboard? Though we would still say it packs a lot into a $90 board, we would recommend that serious enthusiasts spend a bit more money. The LanParty Ultra-D from DFI is only $20 more, and it has quite a few advantages over the Infinity that will be appreciated by more ambitious overclockers. The Ultra-D is basically the same as the SLI-D, only without official SLI support. Motherboards based on ATI's latest chipset also show promise – check out our motherboard reviews for more details on specific motherboards.
We could have tried several different motherboards to see if we could achieve better results, but this isn’t a motherboard or RAM article, even though it has aspects of both types of reviews. This is merely intended as an aid in showing people what can be achieved using the options available with various RAM types on one motherboard with one CPU. In other words, don’t read too much into the memory results. Use them as a guideline for optimizing your own system performance.
We mentioned before that additional RAM ratios would be helpful, and higher end motherboards like the DFI LanParty series often provide them. The Infinity board is limited to DDR400, DDR333, DDR300, DDR266, and DDR200 – at least with the current BIOS. In reality, these are not exact speeds but rather the maximum speed at which the RAM will run with the CPU at stock speed. RAM speed on AMD K8 systems is derived from the CPU speed. With our X2 3800+, “DDR400” results in a CPU/10 RAM divider. 2000/10 = 200 MHz. The 10X multiplier actually makes for very nice RAM speeds, as CPU/12 = 166.7 MHz, CPU/15 = 133.3 MHz, and CPU/20 = 100 MHz. The DDR300 setting is the only one that’s off, as 2000/14 = 143 MHz.
With other motherboards, you may get several additional memory ratios, including those above DDR-400. This provides additional options for reaching maximum performance. In the end, the memory ratios come down to one point. All things being equal (i.e. with identical timings), higher bandwidth will be faster. It may not be a lot faster, but it could be a difference of several percent.
Was that a third strike against the Infinity motherboard? Though we would still say it packs a lot into a $90 board, we would recommend that serious enthusiasts spend a bit more money. The LanParty Ultra-D from DFI is only $20 more, and it has quite a few advantages over the Infinity that will be appreciated by more ambitious overclockers. The Ultra-D is basically the same as the SLI-D, only without official SLI support. Motherboards based on ATI's latest chipset also show promise – check out our motherboard reviews for more details on specific motherboards.
We could have tried several different motherboards to see if we could achieve better results, but this isn’t a motherboard or RAM article, even though it has aspects of both types of reviews. This is merely intended as an aid in showing people what can be achieved using the options available with various RAM types on one motherboard with one CPU. In other words, don’t read too much into the memory results. Use them as a guideline for optimizing your own system performance.
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TheHolyLancer - Wednesday, December 21, 2005 - link
i that since this is an OC thread, they should have used a DFI NF4 Ultra-D or a Expert, they have a 4V jumper that allows you to take DRAM voltage into 4 V (i hope no one does though)JarredWalton - Thursday, December 22, 2005 - link
The higher voltages would have helped the VX RAM a bit. I may shift to a LanParty SLI-DR for the cooling test... or at least try it at some point to see how much of a difference it makes in performance.KingofCamelot - Wednesday, December 21, 2005 - link
I noticed that the BF2 demo file for v1.12 did not work. The bf2bench.demo file needs to be changed for it to work. The bf2bench.demo file can be opened in Notepad, and the following changes need to be made.These lines:
demo.camerafile mods\bf2\Demos\jw112.bf2cam
demo.demofile mods\bf2\Demos\jw112.bf2demo
Need to be changed to:
demo.camerafile mods\bf2\Demos\jwanandtech112.bf2cam
demo.demofile mods\bf2\Demos\jwanandtech112.bf2demo
JarredWalton - Thursday, December 22, 2005 - link
Thanks! I've corrected the file and uploaded the new version.--Jarred Walton
tayhimself - Thursday, December 22, 2005 - link
Hey Jared,This was a very well written article. You were thorough with the benchmarks almost to a fault. I liked your introductory and ending commentary. Your first article was just as good.
Props!
sxr7171 - Thursday, December 22, 2005 - link
Agreed. This was a quality job for sure and the questions he raises at the end are very pertinent. I'm sure he'll come up with the answers.ElFenix - Wednesday, December 21, 2005 - link
i assume you used the stock heat sink/fan unit?JarredWalton - Wednesday, December 21, 2005 - link
Er, sorry I forgot to mention that. I used an XP-90 with a 3000 RPM 92mm fan (generic fan). I'll make a note of that, since that's important information. The followup looking at cooling options will use a retail HSF as well as the XP-90, an Asetek MicroChill, and an Asetek WaterChill. (Why Asetek? Because they asked me to review their two products.)Furen - Wednesday, December 21, 2005 - link
How come the graphs arent zeroed? I suppose it'd be pretty much a bunch of overlapping straight lines if they were but having a graph that shows framerate from 63.5 to 65.0 is not much better.JustAnAverageGuy - Wednesday, December 21, 2005 - link
Yeah, the graphs could be a bit misleading unless you look at what the lines actually represent.The difference between the OCZ PC4800 and everything else looks huge in the http://images.anandtech.com/reviews/cpu/amd/athlon...">Doom 3 graph @ 1600x1200 4xAA, but if you actually look at the lines, the difference is less than 1 frame per second.