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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Furen - Monday, October 3, 2005 - link
Actually, Winchesters are pretty bad overclockers. They were even worse overclockers than newcastles and clawhammers back when they came out, which is why the FX-55 was clawhammer based rather than Winchester based.ksherman - Monday, October 3, 2005 - link
hmmm... Im running a 3000+ winchester, and ive got it to 2.56GHz... thats quite an over clock if you ask me... you would probably be the first person I have EVER say that the winchesters do not OC well...ksherman - Monday, October 3, 2005 - link
is there any performance hit when using memory dividers? I have heard that there is, as the memory and CPU are running on different frequencies... and is it better to keep you RAM @ DDR400, and use dividers or run the RAM @ DDR480?ShadowVlican - Monday, October 3, 2005 - link
so i'm guessing basically, A64's prefer low latency than high frequencyJarredWalton - Monday, October 3, 2005 - link
Pretty much. If you think about it, 10x240 with DDR333 setting is actually identical to 12x200 with DDR400 setting. The RAM is at DDR400 in either case. The difference between a 960 MHz HT speed and 1000 MHz HT speed is... well, if you measure more than a 1% difference, I'd be surprised. :)Wesley Fink - Monday, October 3, 2005 - link
Memory dividers DO make a difference in performance on the Intel platform, where the memory controller is in the chipset and latency is relatively high. Basically, the architecture derives memory ratios with added overhead which can definitely impact performance, and 1:1 memory ratio is best.However, the memory controller on the Athlon 64 is on the processor and memory frequencies are derived from HT on the A64, without adding overhead. That means, theoretically, memory dividers should have NO impact at all on Athlon 64 memory performance - everything else being equal (which it rarely is).
ksherman - Monday, October 3, 2005 - link
well i decided to go for the RAM dividers... upto 2.56GHz, memory using the 5/6 divider (DRAM/FSB) RAM @ DDR466 @ 2-2-2-7 3.3V! was at 2.13Ghz, since I didnt want to use memory dividers. so a nice jump in speed! now I just got to find do some benchies! BTW- I am using a DFI Ultra-D and it is the greatest board I have ever owned! havent done the SLI mod yet, but I dont need toksherman - Monday, October 3, 2005 - link
hmm... guess if i read the WHOLE article... ;-)good article though! I highly reccomend the 'Value VX' RAM aka OCZ Value RAM, since when you put enough voltage into it (3.2V in my case) it overclocks like a charm! Im getting DDR 480 with tight timings (not EXATLY sure, but something 2-2-3-8 1T)
Garyclaus16 - Monday, October 3, 2005 - link
Well,...the article states that there have been performance hits with higher dividers. Best way to find out with yourself is to do your own benches! No two systems will overclock exactly the same, so the best way to figure something out is to try it on your own..Aquila76 - Monday, October 3, 2005 - link
If your RAM will run stably at DDR480, leave it. I had to drop mine down becase there's some issue with the mobo higher than 250MHz.