Investigations into Socket 939 Athlon 64 Overclocking
by Jarred Walton on October 3, 2005 4:35 PM EST- Posted in
- CPUs
The Overclocking Platform
While the choice of processor certainly plays a major role in any overclocking endeavor, it is by no means the only meaningful part. Anyone who has tried their hand at overclocking can attest to the importance of choosing the proper motherboard. The motherboard choice also dictates the chipset and BIOS, and while many chipsets for Athlon 64 do well with overclocking, NVIDIA's nForce4 remains the current champion. (ATI's upcoming Crossfire chipsets hold a lot of promise, but they're only just becoming available at retail, so we will be using nForce4 for this article.)
The chipset still plays a secondary role to the BIOS, however. ASUS' A8V Deluxe showed that a great BIOS implementation could achieve good overclocking results with a VIA chipset. Conversely, a great chipset with a poor BIOS can seriously limit overclocking potential. We saw this in our nForce4 Ultra Motherboard Roundup, where despite using the same chipset, the maximum overclocks were relatively scattered. The design of the motherboards also played a part in those results, of course, as better voltage regulation, cooling, layout, etc. can impact stability. The good news is that BIOS updates are possible and can improve performance without changing the motherboard. The bad news is that it is rare to actually get substantially improved overclocking performance with a BIOS update. If the board manufacturer didn't feel that it was important enough to really focus on overclocking performance with the initial BIOS, they aren't likely to change their mind.
The above points all combine to create the idea of choosing a board maker that has a reputation for overclocking. That's generally sound advice, and there are quite a few companies that do more than pay lip service to the enthusiast market. Abit, ASUS, DFI, EPoX, Gigabyte, and MSI are all pretty good about catering to the overclocking crowd, although some products might still fall a bit short. Albatron, Aopen, Biostar, Chaintech, ECS, Foxconn, Jetway and Soltek (and any others that we failed to list) are less of a sure thing with overclocking support, though we would probably place Albatron, Chaintech, and Soltek above the others in that list. The final word can only be found on a board by board basis, of course, so look around for reviews before purchasing a motherboard with the intent to overclock.
At this point in time, the favored overclocking boards for AMD systems are all from the same place: DFI. We're comfortable in saying that's no accident, as DFI has pushed the limits in supported voltage levels for CPUs and RAM, and they have consistently come out at or near the top of our overclocking tests. Are you guaranteed to reach high overclocks with a DFI board? No. Could you reach higher speeds with a different brand? It's entirely possible - there is an element of luck involved with overclocking, as even two parts off the same assembly line one after the other may not reach identical performance levels. We're going to use a DFI board in this article. The EPoX 9NPA+ Ultra also received our Gold Editor's Choice award in the nForce 4 Ultra roundup, so it should offer similar results. If another board provides the necessary options, you can likely get roughly the same results; however, this article is not intended to be a full motherboard roundup/review. Let's take a minute to look a little closer at the motherboard features.
While the choice of processor certainly plays a major role in any overclocking endeavor, it is by no means the only meaningful part. Anyone who has tried their hand at overclocking can attest to the importance of choosing the proper motherboard. The motherboard choice also dictates the chipset and BIOS, and while many chipsets for Athlon 64 do well with overclocking, NVIDIA's nForce4 remains the current champion. (ATI's upcoming Crossfire chipsets hold a lot of promise, but they're only just becoming available at retail, so we will be using nForce4 for this article.)
The chipset still plays a secondary role to the BIOS, however. ASUS' A8V Deluxe showed that a great BIOS implementation could achieve good overclocking results with a VIA chipset. Conversely, a great chipset with a poor BIOS can seriously limit overclocking potential. We saw this in our nForce4 Ultra Motherboard Roundup, where despite using the same chipset, the maximum overclocks were relatively scattered. The design of the motherboards also played a part in those results, of course, as better voltage regulation, cooling, layout, etc. can impact stability. The good news is that BIOS updates are possible and can improve performance without changing the motherboard. The bad news is that it is rare to actually get substantially improved overclocking performance with a BIOS update. If the board manufacturer didn't feel that it was important enough to really focus on overclocking performance with the initial BIOS, they aren't likely to change their mind.
The above points all combine to create the idea of choosing a board maker that has a reputation for overclocking. That's generally sound advice, and there are quite a few companies that do more than pay lip service to the enthusiast market. Abit, ASUS, DFI, EPoX, Gigabyte, and MSI are all pretty good about catering to the overclocking crowd, although some products might still fall a bit short. Albatron, Aopen, Biostar, Chaintech, ECS, Foxconn, Jetway and Soltek (and any others that we failed to list) are less of a sure thing with overclocking support, though we would probably place Albatron, Chaintech, and Soltek above the others in that list. The final word can only be found on a board by board basis, of course, so look around for reviews before purchasing a motherboard with the intent to overclock.
At this point in time, the favored overclocking boards for AMD systems are all from the same place: DFI. We're comfortable in saying that's no accident, as DFI has pushed the limits in supported voltage levels for CPUs and RAM, and they have consistently come out at or near the top of our overclocking tests. Are you guaranteed to reach high overclocks with a DFI board? No. Could you reach higher speeds with a different brand? It's entirely possible - there is an element of luck involved with overclocking, as even two parts off the same assembly line one after the other may not reach identical performance levels. We're going to use a DFI board in this article. The EPoX 9NPA+ Ultra also received our Gold Editor's Choice award in the nForce 4 Ultra roundup, so it should offer similar results. If another board provides the necessary options, you can likely get roughly the same results; however, this article is not intended to be a full motherboard roundup/review. Let's take a minute to look a little closer at the motherboard features.
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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