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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JarredWalton - Wednesday, December 21, 2005 - link
Ugh - at a comment on is an article that true special attention to the fact that the graphs aren't zeroed. I think in the process of tweaking article to get things to look right, I accidentally deleted that paragraph. I have now http://www.anandtech.com/cpuchipsets/showdoc.aspx?...">added to paragraph back in.If I start all the graphs at zero, everything overlaps and you can't really see what's going on. In some cases, everything is still overlapped a lot (FEAR). I normally hate nonzero graphs, but when the results are all so close together, that's no good either for readability.
BigLan - Wednesday, December 21, 2005 - link
Well, if everything is overlapping that much, it's likely that the results are too close to be really meaningful. The FEAR graph is a pretty good example of <a href="http://www.amazon.com/gp/product/0393310728/>Ho...">http://www.amazon.com/gp/product/0393310728/"... to Lie With Statistics</a> ;)BigLan - Wednesday, December 21, 2005 - link
^ Still need my edit function for comments. :pDammit
JustAnAverageGuy - Wednesday, December 21, 2005 - link
:)JarredWalton - Wednesday, December 21, 2005 - link
^ Still need my edit function for comments. :pThat was supposed to say, "I had a comment in this article that drew special...." That will teach me to trust my speech recognition software.
Hacp - Wednesday, December 21, 2005 - link
I have found that past 2.6, the heat and temps increase dramatically. Nice to know that anandtech got the same results as well.Yianaki - Wednesday, December 21, 2005 - link
SuperPI crashes help! I have a Opteron 165 with 1 gig of value PC4000 kingmax ram at 133 2.5-4-4-8 2t. Board is OC to 1.4v at 9x277 = 2.494. I have run two torture versions of prime 95 (one of the CPU intensive, one of the ram intensive) on each processor, for a total of 4 prime95's. At the same time I run 3dmark 2005. At the same time I run winamp with visualizations on. I leave this on all night 9hrs+ in a loop. No errors at all. No buggyness at all. I game for 3 or 4 hours at a time and no problems.But I just read this article and SuperPI was mentioned and I never used that before and I tried it. It wouldn't work unless I lowered my overclock to 2.00 which is unacceptable to my sorry ass. I KNOW my system is unstable. I just was wondering if it mattered as the computer is completely stable. I am guessing that prime95 just rounds off answers and they don't have to be exact whereas I am guessing that SuperPI's answers are already known to be exact. Actually SuperPI runs fine but if I open up a second copy from a second folder and attach the affinity to both processors SuperPI will have errors as soon as I start it 1second of starting the 2nd process. Any ideas??
Could it possibly be my motherboard or ram as both are 'value' versions not OC specialty items. I have already played around with rendering divx movies and playing doom no problem. Will I probably have some problem down the road or like some small encoding error or dvd writing error that is due to my overclock. I Overclocked my old PII too high and it was spewing out bad math. I did all these chem reports in college and was getting completly off the wall numbers (I never tested my PII oc in prim95). Is this the same or does the error correcting in my programs that I am running in XP make this point moot.
Man I wish I never read about superPI poo :<
Furen - Wednesday, December 21, 2005 - link
Superpi and prime95 work differently. I think superPI is more reliant on memory bandwidth (if you're doing something like 32M superPi) so your ram may be the problem (I, personally, like crucial ram, I've never had any problems with it at all, and its not much more expensive than the generic crap). If your system doesnt crash when you're doing whatever it is that you do on your computer then you're fine, though, but I'd still try to work on the ram to see if you can get it to be superpi stable.Yianaki - Wednesday, December 21, 2005 - link
It just gets wierder and wierder... If I don't set the affinity manually in the task manager it will run through to the end and the CPU's will both be at 100%. But if I set them manually in the task manager before I start 32M the second one I start always crashes? I am guessing that the task manager isn't running the processors at 100% or something, as the windows task manager is automatically putting the loads on the two cpus and for a milisecond one isn't doing anything???? My Memory is up to 95% utilization... This proggie sucks if you ask me.Yianaki - Wednesday, December 21, 2005 - link
Thanks for the feedback. BTW it is Kingmax Super Ram, Dual channel mate. My motherboard is a ASRock 939 dual sata-2. Bought it because it runs AGP and PCIe quickly. I have my ram underclocked normally it can run at 200 but is running at 133 normally, I also lowered it to 100. I lowered all the timings lower than what the spd says. None of these things help... I am really confused. I run the Blend (ram intensive) test on each processor at the same time as the FFT test in prime 95. Memory usage goes up to 1.5 gigs total (I only have a gig), so that is using all the memory + page. But there is no error at all. I am a little dumbfounded but I have been thinking about it and my computer doesn't have any 'random' errors which is fine. Cept for firefox 1.5 and it had the same occasional problems before my upgrade. Oh well hope everything stays stable. Thanks for the feedback.