Investigations into Socket 939 Athlon 64 Overclocking
by Jarred Walton on October 3, 2005 4:35 PM EST- Posted in
- CPUs
Introduction
Note: This article is an in-depth look at overclocking. We'll cover how to do it, what sort of performance you can achieve, problems and potential solutions, etc. Overclocking can be frustrating, rewarding, fun, and dangerous. We don't mean "burn the house down" dangerous, but you could certainly end up ruining some or all of your computer components. We take no responsibility for any difficulties or losses you may experience by using the information in this article, and we certainly take no responsibility for any damage that may occur to any person, place, or object. The manufacturers of the parts that we are using are also not accountable for any loss/damage that may occur - most companies void your warranty for overclocking. It's a risk, and it's your risk - proceed with caution. Finally, overclocking is never a "guaranteed result". You may or may not match the results that we achieve. We'll be happy to offer suggestions if you need them, as will many of our forum members. Patience and research are part of overclocking as well, so please understand that you may have to do some work on your own. If you can accept those warnings, we hope that you enjoy this article.
Back in the day, overclocking was in some ways simpler than what we see now. You would typically buy a mid-range processor and then try to increase the bus speeds as much as possible in order to get the most performance out of your system. Older Pentium chips also allowed you to change the multiplier, so with some luck, you might get your 2.5X multiplier on a Pentium 166 up to 3.0X, resulting in a 33 MHz overclock. Other than a few special chips like the Pentium M and Athlon FX, increasing multipliers is no longer possible. The modification of bus speeds can still be used, but it isn't necessarily the best or only way to try to overclock your system. We have mentioned overclocking performance in many articles, but we haven't taken the time to really explore all the options out there. We also know that current Intel and AMD setups have very different options and performance when overclocking is used, so we want to look at that as well.
Before we branch out into AMD vs. Intel comparisons, however, let's talk about the past top performers. The Celeron 300A is fondly remembered by many people, and with good reason. Yes, we have had some other good parts in the intervening years, like the 2.4 GHz Northwood cores, the low end Prescott cores, and the Athlon XP-M Barton parts. However, when you look at the 50% overclock of the Celeron 300A (and it wasn't just possible, it was common), none of the other parts have really ever approached that level of overclocking without some serious investment in cooling options. (Some people even managed to get the 300A to 504 MHz - an amazing 68% overclock!) Northwood's 2.4 GHz to 3.2 GHz is still an impressive 33% overclock. The 2.4 GHz to 3.6 GHz Prescott overclock (using the 2.4A) actually matches the 50% of the 300A, but you sacrifice some features (HyperThreading and high FSB speeds) with the lower model parts. Meanwhile, the overclocking darling that was the XP-M 2500+ "only" managed a typical overclock of 1.87 GHz to 2.4 GHz, a 29% overclock.
That brings us to the part that we're investigating today. It is arguably the best overclocking platform since the old Celeron 300A: AMD's Venice core. One thing that we didn't mention above is the role that price plays for many overclockers. Sure, the Athlon-FX can reach clock speeds and performance that most other chips only dream about, but at a cost of roughly $900 just for the processor, a lot of people will only read about it. What made the 300A so attractive was that it was not only a monster overclocking chip, but it cost around $150 and competed with $500 chips. That's why the 2.4C and 2.4A Pentium 4 are also well regarded; they cost under $200 and could compete with chips that cost two to three times as much. The price of entry for the cheapest Venice core (the 3000+) is once again very low; $120 for the OEM model, or $145 for the retail version.
We'll get into the details more in a moment, but for now, we'll just say that the 3200+ may actually be a better choice, and that's what we are using for this article. We are also using the retail model, and some people will say that retail parts tend to overclock better than the OEM chips. We'll simulate 3000+ overclocking using a 9X CPU multiplier, but that may or may not be an entirely accurate representation of 3000+ overclocking performance. In general, though, what we're hearing is that almost all of the Venice cores can run at very high clock speeds with a bit of effort, so there isn't a huge difference between 3000+ parts binned for 1.8 GHz and 3800+ parts binned for 2.4 GHz. AMD has simply set the package to use a maximum 9X multiplier on the former and a 12X multiplier on the latter. Talking about CPU multipliers leads us into the real meat of the discussion, though, so let's get into it.
Note: This article is an in-depth look at overclocking. We'll cover how to do it, what sort of performance you can achieve, problems and potential solutions, etc. Overclocking can be frustrating, rewarding, fun, and dangerous. We don't mean "burn the house down" dangerous, but you could certainly end up ruining some or all of your computer components. We take no responsibility for any difficulties or losses you may experience by using the information in this article, and we certainly take no responsibility for any damage that may occur to any person, place, or object. The manufacturers of the parts that we are using are also not accountable for any loss/damage that may occur - most companies void your warranty for overclocking. It's a risk, and it's your risk - proceed with caution. Finally, overclocking is never a "guaranteed result". You may or may not match the results that we achieve. We'll be happy to offer suggestions if you need them, as will many of our forum members. Patience and research are part of overclocking as well, so please understand that you may have to do some work on your own. If you can accept those warnings, we hope that you enjoy this article.
Back in the day, overclocking was in some ways simpler than what we see now. You would typically buy a mid-range processor and then try to increase the bus speeds as much as possible in order to get the most performance out of your system. Older Pentium chips also allowed you to change the multiplier, so with some luck, you might get your 2.5X multiplier on a Pentium 166 up to 3.0X, resulting in a 33 MHz overclock. Other than a few special chips like the Pentium M and Athlon FX, increasing multipliers is no longer possible. The modification of bus speeds can still be used, but it isn't necessarily the best or only way to try to overclock your system. We have mentioned overclocking performance in many articles, but we haven't taken the time to really explore all the options out there. We also know that current Intel and AMD setups have very different options and performance when overclocking is used, so we want to look at that as well.
Before we branch out into AMD vs. Intel comparisons, however, let's talk about the past top performers. The Celeron 300A is fondly remembered by many people, and with good reason. Yes, we have had some other good parts in the intervening years, like the 2.4 GHz Northwood cores, the low end Prescott cores, and the Athlon XP-M Barton parts. However, when you look at the 50% overclock of the Celeron 300A (and it wasn't just possible, it was common), none of the other parts have really ever approached that level of overclocking without some serious investment in cooling options. (Some people even managed to get the 300A to 504 MHz - an amazing 68% overclock!) Northwood's 2.4 GHz to 3.2 GHz is still an impressive 33% overclock. The 2.4 GHz to 3.6 GHz Prescott overclock (using the 2.4A) actually matches the 50% of the 300A, but you sacrifice some features (HyperThreading and high FSB speeds) with the lower model parts. Meanwhile, the overclocking darling that was the XP-M 2500+ "only" managed a typical overclock of 1.87 GHz to 2.4 GHz, a 29% overclock.
That brings us to the part that we're investigating today. It is arguably the best overclocking platform since the old Celeron 300A: AMD's Venice core. One thing that we didn't mention above is the role that price plays for many overclockers. Sure, the Athlon-FX can reach clock speeds and performance that most other chips only dream about, but at a cost of roughly $900 just for the processor, a lot of people will only read about it. What made the 300A so attractive was that it was not only a monster overclocking chip, but it cost around $150 and competed with $500 chips. That's why the 2.4C and 2.4A Pentium 4 are also well regarded; they cost under $200 and could compete with chips that cost two to three times as much. The price of entry for the cheapest Venice core (the 3000+) is once again very low; $120 for the OEM model, or $145 for the retail version.
We'll get into the details more in a moment, but for now, we'll just say that the 3200+ may actually be a better choice, and that's what we are using for this article. We are also using the retail model, and some people will say that retail parts tend to overclock better than the OEM chips. We'll simulate 3000+ overclocking using a 9X CPU multiplier, but that may or may not be an entirely accurate representation of 3000+ overclocking performance. In general, though, what we're hearing is that almost all of the Venice cores can run at very high clock speeds with a bit of effort, so there isn't a huge difference between 3000+ parts binned for 1.8 GHz and 3800+ parts binned for 2.4 GHz. AMD has simply set the package to use a maximum 9X multiplier on the former and a 12X multiplier on the latter. Talking about CPU multipliers leads us into the real meat of the discussion, though, so let's get into it.
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JarredWalton - Monday, October 3, 2005 - link
It's tough to say how things will pan out long-term. 1.650V seems reasonably safe to me, but I wouldn't do it without a better HSF than the stock model. The 1.850V settings made me quite nervous, though. If you can get your CPU to run at 1.600V instead of 1.650V, that would be better, I think. There's also a possibility that slowing down your RAM slightly might help the CPU run at lower voltages. I'd sacrifice 5% to run what I consider a "safer" overclock, though really the thought of frying a $140 CPU doesn't concern me too much. That's less than any car repair I've had to make....cryptonomicon - Monday, October 3, 2005 - link
well for most overclocks a reasonable ("safe") increase of voltage is 10-15%. however that is just a guideline, it may be more or less. there is sort of a way to find out: if you work on overclocking to the maximum of your chip while scaling the voltage, you will eventually hit a place where you have to increase the voltage dramatically just to get up the next FSB bump. for example if you are at 2500mhz and 1.6v, then it takes 1.75v just to get to 2600mhz, then you have hit that boundary and should go back down immediatly. when the voltage to cpu speed ratio is scaling consistently, then things are fine. but once the voltage required becomes blatently unbalanced, that is the logical time to stop... unless you have no concern for the longetivity of the chip.Ecmaster76 - Monday, October 3, 2005 - link
Finally goaded me into overclocking my P4 2.4c. I had been planning for a while but never bothered too.So I got bored and set the FSB to 250mhz (I went for my goal on my first try!) with a 5:4 (still DDR400) memory ratio. It works great at stock cooling + stock voltage. I will have to do some long term analysis of stability but since I am building a new system before the years end I don't really care if it catches on fire. Well as long as it doesn't melt some of my newer nerd toys that are attached to it.
lifeguard1999 - Monday, October 3, 2005 - link
I am running an AMD Athlon 64 3000+ Processor (Venice) @ 2.7 GHz, stock HSF; 1.55V Vcore; DFI LANPARTY nF4 SLI-DR. It was cool seeing you run something similar to my setup. I run value RAM and it seems that I made the right choice for me (giving up at most 5% performance). You ran at Vcores much higher than I do, so it was interesting to see the CPU handle that.The only thing I would add to this article is a paragraph mentioning temperatures that the CPU experienced.
mongoosesRawesome - Monday, October 3, 2005 - link
yes, i second that. temps at those volts using your cpu cooler as well as with maybe a few other coolers would be very helpful. also, if you could do a few tests using different coolers to see when temps hold you back.JarredWalton - Monday, October 3, 2005 - link
I've got some tests planned for cooling in the near future. I'll be looking at CPU temps for stock (2.0 GHz) as well as 270x10 with 1.750V. I've even got a few other things planned. My particular chip wouldn't POST at more than 2.6 GHz without at least 1.650V, but that will vary from chip to chip. The XP-90 never even got warm to the touch, though, which is pretty impressive. Even with an X2 chip, it barely gets above room temperature. (The core is of course hotter, but not substantially so I don't think.)tayhimself - Tuesday, October 4, 2005 - link
Good article, but your Vcore seems to scale up with most of the increments in speed? Did you HAVE TO raise the vcore? Usually you can leave the vcore until you really have to start pushing. Comments?JarredWalton - Tuesday, October 4, 2005 - link
2.20GHz was fine with default 1.300. 2.40GHz may have been okay; increasing the Vcore to 1.40V seemed to stabilize it a bit, though it may not have been completely necessary. 2.60GHz would POST with 1.450V, but loading XP locked up. 1.550V seemed mostly stable, but a few benchmarks would crash. 2.70GHz definitely needed at least 1.650V, and bumping it up a bit higher seemed to stabilize it once again. 2.80GHz was questionable at best even at 1.850V with the current cooling configuration. It wouldn't load XP at 2.80GHz at 1.750V, though.JarredWalton - Tuesday, October 4, 2005 - link
My memory on the voltages might be a bit off. Personal experimentation will probably be the best approach. I think I might have erred on the high side of required voltage. Still, past a certain point you'll usually need to scale voltage a bit with each bump in CPU speed. When it starts scaling faster - i.e. .1V more to get from 2700 to 2800 MHz - then you're hitting the limits of the CPU and should probably back off a bit and call it good.tayhimself - Tuesday, October 4, 2005 - link
Thanks a lot for your replies. Looks like there is a fair bit of overclocking even if you dont increase the Vcore too much to help save power/noise etc.Cheers