Investigations into Socket 939 Athlon 64 Overclocking
by Jarred Walton on October 3, 2005 4:35 PM EST- Posted in
- CPUs
System Settings
We have a bunch of screenshots from CPU-Z showing the CPU and Memory tabs, covering most of the settings that we used. Rather than linking 44 images, though, we're just going to provide a single Zip file of all the screens. One thing that became immediately clear is that the BIOS voltages were almost never reflected in the CPU-Z results. Which one is more accurate is impossible to say, short of busting out a voltmeter (and knowing where to attach it).
We did not remember to get a screenshot of every single configuration tested, since we went back to fill in the blanks on CPU performance after running the initial benchmarks. However, you can get the settings used in the following table. If you have a motherboard that doesn't support the same settings that we used, you may or may not be able to reach a specific overclock.
Disclaimer: Many of the tested voltages on the CPU are probably higher than necessary. After trying for 10x280 with up to the maximum voltage possible from the motherboard, I was probably a bit too lenient on turning voltages back to normal. These are more or less the settings I used during the testing - there may be a few errors in record keeping. If you are looking for long-term stability and you can get the system to run stable at 1.450V instead of 1.650V, that would be a wise decision. The results in the following table are merely intended as an initial reference point.
Note how CPU voltages scaled rapidly as we neared the highest overclock levels. We didn't spend a lot of time trying to get things running stably at a lower voltage level, so mostly, we went in .05V increments - again, you might be able to get better results. If we experienced a crash during our benchmarking, we would try to increase the CPU and/or chipset voltage to get the tests to run stable. If that didn't work, we resorted to tweaking memory timings, generally by increasing latencies until we found a stable setting. Once we went from CL2 to CL2.5, we didn't spend the time trying to get 2.5-2-2, 2.5-3-2, or anything other than 2.5-3-3 (or higher latencies) to run stably.
With our performance RAM, we kept it at a steady 2.8V setting. We did try 2.9V on some of the higher overclocks, particularly where we had to drop from the PC3200 to PC2700, but we couldn't get 1T timings at PC3200 above a 280 MHz CPU bus speed. The value RAM was kept at a steady 2.6V setting and 2.5-3-3-8-1T timings, except in a few cases where we had to run with 2T timings. We tried to get 3-4-4-8-1T instead, but at 9x300, we could not run the value RAM without the 2T setting.
You'll notice the "crash" and "unstable" comments on several of the highest overclock attempts. "Crash" means that we were unable to run many of the tests due to repeated lockups, reboots, etc. "Unstable" means that we were able to get benchmark results for all (or nearly all tests), but programs might crash at times. For example, Far Cry might crash at 1024x768 4xAA on the first attempt, but rebooting and starting again from that point would complete the tests. We tried to run all of the gaming benchmarks in order without rebooting, which will keep system temperatures higher than letting the GPU cool down for a couple of minutes while we reboot. We won't include the settings that crashed in our results, but we did include the unstable results. We'll be using these unstable settings for some cooling tests in the future to see if a change in HSF will help - and hopefully even allow higher overclocks.
A last comment is that we didn't fully benchmark all of the settings listed in the charts. We tested 1800, 2000, 2200, 2400, 2600, and 2700 MHz. We also tested 2800 MHz on a couple of configurations, although stability was iffy at best. In order to provide a linear scale (so that the results at 2700 aren't skewed), we interpolated the in-between scores. This is a problem with the graphing capability that we have within Excel. We did run some quick tests at each setting, though, just to verify that we could POST and complete PCMark04/PCMark05. In case you're wondering, the entire benchmark suite takes around 4 to 5 hours to complete. That will hopefully explain why we didn't run the additional tests or spend a lot of time fine-tuning each tested setting.
And now, on with the benchmarks.
We have a bunch of screenshots from CPU-Z showing the CPU and Memory tabs, covering most of the settings that we used. Rather than linking 44 images, though, we're just going to provide a single Zip file of all the screens. One thing that became immediately clear is that the BIOS voltages were almost never reflected in the CPU-Z results. Which one is more accurate is impossible to say, short of busting out a voltmeter (and knowing where to attach it).
We did not remember to get a screenshot of every single configuration tested, since we went back to fill in the blanks on CPU performance after running the initial benchmarks. However, you can get the settings used in the following table. If you have a motherboard that doesn't support the same settings that we used, you may or may not be able to reach a specific overclock.
Disclaimer: Many of the tested voltages on the CPU are probably higher than necessary. After trying for 10x280 with up to the maximum voltage possible from the motherboard, I was probably a bit too lenient on turning voltages back to normal. These are more or less the settings I used during the testing - there may be a few errors in record keeping. If you are looking for long-term stability and you can get the system to run stable at 1.450V instead of 1.650V, that would be a wise decision. The results in the following table are merely intended as an initial reference point.
Click to enlarge.
Note how CPU voltages scaled rapidly as we neared the highest overclock levels. We didn't spend a lot of time trying to get things running stably at a lower voltage level, so mostly, we went in .05V increments - again, you might be able to get better results. If we experienced a crash during our benchmarking, we would try to increase the CPU and/or chipset voltage to get the tests to run stable. If that didn't work, we resorted to tweaking memory timings, generally by increasing latencies until we found a stable setting. Once we went from CL2 to CL2.5, we didn't spend the time trying to get 2.5-2-2, 2.5-3-2, or anything other than 2.5-3-3 (or higher latencies) to run stably.
With our performance RAM, we kept it at a steady 2.8V setting. We did try 2.9V on some of the higher overclocks, particularly where we had to drop from the PC3200 to PC2700, but we couldn't get 1T timings at PC3200 above a 280 MHz CPU bus speed. The value RAM was kept at a steady 2.6V setting and 2.5-3-3-8-1T timings, except in a few cases where we had to run with 2T timings. We tried to get 3-4-4-8-1T instead, but at 9x300, we could not run the value RAM without the 2T setting.
You'll notice the "crash" and "unstable" comments on several of the highest overclock attempts. "Crash" means that we were unable to run many of the tests due to repeated lockups, reboots, etc. "Unstable" means that we were able to get benchmark results for all (or nearly all tests), but programs might crash at times. For example, Far Cry might crash at 1024x768 4xAA on the first attempt, but rebooting and starting again from that point would complete the tests. We tried to run all of the gaming benchmarks in order without rebooting, which will keep system temperatures higher than letting the GPU cool down for a couple of minutes while we reboot. We won't include the settings that crashed in our results, but we did include the unstable results. We'll be using these unstable settings for some cooling tests in the future to see if a change in HSF will help - and hopefully even allow higher overclocks.
A last comment is that we didn't fully benchmark all of the settings listed in the charts. We tested 1800, 2000, 2200, 2400, 2600, and 2700 MHz. We also tested 2800 MHz on a couple of configurations, although stability was iffy at best. In order to provide a linear scale (so that the results at 2700 aren't skewed), we interpolated the in-between scores. This is a problem with the graphing capability that we have within Excel. We did run some quick tests at each setting, though, just to verify that we could POST and complete PCMark04/PCMark05. In case you're wondering, the entire benchmark suite takes around 4 to 5 hours to complete. That will hopefully explain why we didn't run the additional tests or spend a lot of time fine-tuning each tested setting.
And now, on with the benchmarks.
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JarredWalton - Wednesday, October 5, 2005 - link
Sorry if I missed this in the article. The reason a 3200+ may be better is the 10X multiplier vs. 9X. Sure, the DFI board used worked pretty well at either setting, but there are many boards that won't handle much above 250 MHz CPU bus stably. Needless to say, there's a reason 2800 MHz was only included at one setting. While it still wasn't stable, it would actually run most benchmarks at 10x280. 9x311 wouldn't even load Windows half the time. The extra $50 for added flexibility is also nice: you can try 9x300, 10x270, PC3200, PC2700, etc. to find the most stable, highest performing option.Bakwetu - Wednesday, October 5, 2005 - link
Thanks for a great article. I haven't been following the development so carefully since I upgraded last time (with one of the last unlocked Barton 2500+), so this article was a most welcome refresher for me, as I will probably get a x2 3800 rig in the near future.Last time I checked using the naked fingertip to smear out the paste was a big no-no. I have always used either a washed razorblade or fingertip in a clean plastic bag. The Arctic silver once sold without silver was a faked, copied product as far as I know. The real stuff in its many forms over the years has definitely shown that it is a good product.
javalino - Wednesday, October 5, 2005 - link
Frist , great article, Jarred.Second, i m an anand fan since i remember (1999-2000).
Third, Since yours conclusion focus on a dilema about overclock, why spend to much in an overclock symtem(or on a powerfull system) if you target is at games ? (wich is a GPU limited). An 125 bucks , like you said, will be more usefull in a video card.
My idea is an article, about "Benefits, Costs, and Lessons Learned" about build a system for games. How much will be a performance gain from systems running high end cards ,at high resoltion and configurations ( like 1600 x 1200, and with an extra 4xAA 16XAF), with differents system . A FX VS 64(overclock) VS P4 (over) VS P-M VS AMD XP (over of course), for example. The conclusion will be, how much is "needed" to pay for a decent game machine wich is possible to play all current games(and maybe future) with great image quality and performance.
Maybe the answer is obvious, go with the best FPS/price option possible, or maybe not.
AtaStrumf - Tuesday, October 4, 2005 - link
Great article Jarred!!! I really like your choice of value parts and how you criticaly assesed the results based on the bang-for-the-buck. And finally you did away with pages and pages of bar charts, and combined them into line-scaling charts. How long have I been asking for something like that??? Now we can finally see the REAL difference (or lack of it), and analyse results properly, without having to go back and forth between tens of bar charts. Tell Anand to upgrade your graphing engine ASAP.I am a little worried about those voltages though. This sure looks like a bad chip to me (OC wise). WAY too high voltages. I would not go over 1,45 - 1,50 V or else you risk screwing up the chip. You see the memory controller on the chip doesn't like too high voltages and though it will still work, the chip will get slower eventually. Hard to explain really but I know my new 2,2 GHz A64 is faster and much cooler than my old 2,4 GHz A64 (same core - Newcastle, same cooer, same RPM, same case, same ...), which I bought from some crazy overclocker (last time BTW). The 2,4 GHz one gave me really shitty results in FAH for weeks. That's the only explanation a have so far anyway. Maybe you can do an investigaion into this -- burn in one A64 Venice at say 1,6V 24/7 for a few weeks and let's see what happens. I just don't have the $$$ and time to take the risk. I'd be very happy to hear from other forum members on this as well.
Anyway, glad to see at least part of AT is back to the high quality standards we were used to.
AtaStrumf - Tuesday, October 4, 2005 - link
Or maybe it's the SOI process that is to blame for not taking high voltages too kindly, or maybe both, don't know yet, but I would definitely advice caution goint over 1,5V (default for 0,13 mikron SOI chips). Just think about it, that's already a 15% increase. +10% is usualy max that is still considered safe.You just posted that this chip seems to have changed it's behavior (better OC). That may have something to do with the high voltages and it may not be all good. I'd suggest testing it again in a few benchmarks and comparing the results.
JarredWalton - Wednesday, October 5, 2005 - link
Working on it. I think I ended up benching at 1.850V for the 10x280 setting and then not dropping voltages as much as I was supposed to. I'm a little skeptical that a CPU would get slower, though. Usually, they work or they fail. We'll see.My thought on the "safe limit" though: what voltage does the FX-57 run at? Whatever it is, at 10 to 15% to that and you're probably still okay. Good cooling will also help; on the stock HSF, I'd be a lot more nervous going over 1.550V.
OvErHeAtInG - Tuesday, October 4, 2005 - link
Very useful article - thorough yet concise. And I would like to toss in another request: Add to the test a ULi-based motherboard (such as the recently reviewed ASRock 939Dual-SATA2). How do these Venices overclock when you can only feed them +.05v? As I recall the standard AT Clawhammer was used in that review.That would be hugely useful to a lot of us wanting to transition to A64. While the thing to do is probably just get a DFI or other top-end oc'er, what to do for those of us who are not yet ready to upgrade GPUs? On second thought: you could simulate the ASRock motherboard by simply setting the Venices to the lower voltage, on the DFI board, and testing for the max overclock on that. I think that would vary quite a bit from chip to chip, but just to get an idea - how much of a disadvantage is being limited in your voltage? Food for thought.
JarredWalton - Tuesday, October 4, 2005 - link
I played around with voltages a bit more last night. It seems like I can hit about 2.40 GHz with only increasing the CPU voltage to 1.40V, though I didn't run all of the benchmarks to fully test that config. I'm not sure if the CPU has changed behavior over the past month, or if I was just too liberal with the voltages initially.For the ASRock, that Wes managed to get a 500 MHz OC even with the minimal voltage adjustments is promising. Truth be told, the DFI Infinity seems to undervolt the CPU slightly, so 1.500V actually shows up as closer to 1.455V. If the ASRock is exact with the voltages, or even a bit high, I think a 2.4+ GHz overclock is a reasonably safe bet.
OvErHeAtInG - Wednesday, October 5, 2005 - link
Thanks for the info, Jarred. I'm sure there's a thread on this somewhere.... :)araczynski - Tuesday, October 4, 2005 - link
i haven't seen a better argument for not wasting money on the 'better' memory in ages.with those kinds of 'gains' i congratulate the companies for milking everyone with their markups for the 'higher end' components.