AGP Overclocking Survey

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First, I’d like to thank the almost forty people who took the time and effort to measure their systems and email me their results. I was going to mention all of you, but I decided I’d better not list anyone without their permission first, which I’ll do in future surveys.

I asked for this information because I had a theory about what was happening with these AGP cards. I thought that what happens with a Matrox G400 and a few other video cards is that when you overclock a BX board to high FSBs that they automatically shift into AGP 1X mode. Well, my theory was proven wrong, thanks to your help. Thank God for science; it gets us to the right answer.

Most of you had no problem running at 133Mhz FSB or better at an AGP 2X speed. The Matrox cards tended to go to AGP1x at speeds of 100Mhz, but the Nvidia, Voodoo and ATI cards held up well. Even at 150Mhz, some of you were showing AGP transfer rates of 200Mhz or a bit better. A few of you needed to go to AGP 1X to reach very high speeds, but there were plenty who didn’t.

A few other theories went out the window, too. A few have said that disabling sideband helped them reach higher speed. That may be true for some people, but outside of the GeForce users, just about everyone can hit these high speeds with sideband enabled.

Aperture size was another tweak some have suggested could get you to higher speeds. The data shows that folks are hitting high speeds with little aperture sizes and big aperture sizes. So aperture size isn’t a big factor in determining if your system will work.

However, a number of you did report that while you could boot and run ordinary programs at high speeds in Windows, but when it came to running games or 3D benchmarks; you had to lower speeds. So many of those high speeds may be useless once you put some load of them.

Most of you were using late model Abit boards, with a sprinkling of AOpen, Asus and Soyo boards. The motherboard used didn’t seem to matter.


1) You probably can run at 133Mhz or better with a late model video card, and not have the video card stop you in at least non-gaming situations.

Disclaimer: Doing this is solely your responsibility, and someone who is gathering data on this HERE has said that he’s gotten plenty of reports of people burning out video cards doing this, so if it happens to you, you have been warned. You should read and implement the precautions listed in the URL I just mentioned before doing this. If you don’t want to take the chance, you will probably be a lot better off waiting for the Coppermine-128s coming out in March that are likely to let you run at 100Mhz FSB and do about as well as the Coppermine are now.

2) You may have quite a different story playing heavy-duty games at that speed, especially if you are going for 150Mhz FSB. You may well find yourself running at a speed much lower than 150Mhz FSB, which will also reduce your CPU speed significantly.

3) We do not know what are the long-term effects of this overclocking of the transfer rate (which does not improve actual video performance). However, it certainly will not hurt and probably will help to keep your video card and motherboard chips as cool as possible, so use fans and thermal compound for your video card and motherboard chips. You should also consider this to be a temporary expedient until new motherboards come out in the spring.

4) If you are looking for a sure thing and need to be careful with your money, you may want to wait a bit. Not because of the Coppemine CPU itself, that looks fine up to 750-800Mhz. It’s the limitations of other parts of your systems that are likely to be a problem. For those of you who do not already have PC133 memory or the latest motherboards, running at 667Mhz with a 500E or 733Mhz with a 550E may be more realistic than 750 or 825Mhz.

If the 566Mhz Coppermine-128 can run at 850Mhz come March or April (and we don’t know that yet), you should be able to get performance just as good as you’ll get from a Coppermine-256 running at 750Mhz without running into these headaches. It should cost you less too, especially if you find yourself having to upgrade parts of your system. I’m not saying don’t do it, but those who have to be a bit more careful with their overclocking dollars might want to wait until we see what the new Celerons can do in a couple months.

Again, thanks, and we have to do this again sometime. 🙂

Email Ed


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