I'm wanting to toy with overclocking on my GA-7N400 Pro2 mobo + Barton 2600+ CPU, but can't get it to work. Main problem is that the CLK_RATIO switches on the mobo make NO difference. Its as though they're stuck on AUTO setting. Does this CPU need its multiplier unlocked? Should my mobo be doing it anyway? I've read enough forum threads to suggest that it shouldn't need me to do the unlocking, but I'm not totally sure. With CLK_SW set "off" (100MHz FSB), system comes up as 100*11.5 = 1150MHz. With CLK_SW set "on" (AUTO FSB - 333 MHz), the system comes up as 166*11.5 = 1917MHz (2600+). This is all fine. Problem (IMHO) is that the CLK_RATIO dip-switches have no effect on these results. Bios version: F5 (latest) CPU (from WCPUID): Athlon XP, Model A Family/Model/Stepping: Std: 6/10/0. Ext: 7/10/0. L2 Cache: 512K. Incidently, before doing this, I tried setting the FSB to the full 200MHZ in the bios, and the machine refused to boot. Had to do a clr_cmos on the mobo to get it back again. Any suggestions? Ta, sTu.

is it a new cpu? ive heard rumors amd is not allowing overclocking anymore but i dunno any one know?

Bought it about 3 weeks ago. Certainly the 2600+ is quite new in the Barton series... many tech websites still refer to Bartons as just bing 2500/2800/3000/3200. Even one of the info pages on AMDs website doesn't list it. :-\ sTu.

Don't jump from 166 to 200 in one go, go up in small 2-5MHz increments, after each increase, try to boot into Windows, if it does, keep going, if it doesn't, bump the vcore up a little (0.025v at a time) until it does (don't exceed 1.75v on stock cooler, 1.9v with a decent cooler). Once you hit your max FSB, ie. you can't get Windows to boot no matter what you do, give the system a stress test, first try and run 3D Mark 01/03, then run the Sandra burn-in test at 100% utilisation for at least 50 runs. If thats all good, play something intensive like C&C Generals for a while, if all goes well, great, if not, start droping the FSB until you have 100% stability. Don't bother with multiplier adjustments, the 2600+ Barton uses a stock 11.5x multi, at 200FSB that gives you 2.3GHz, that is quite acievable on a Barton core. See how you go.

AMD restricting things wouldn't suprise me given that the 3200 is seemingly the end of the Barton & 32-bit Athlon XP lines (presumably Athlon 64's are the next stage), and that so many are reporting success oc'ing their 2500+'s to at/near_that without hassle.

Thanks for the tips Adam. A few comments/questions: - the problem I had at 200MHz FSB was that it wouldn't even POST. No sign of life. Maybe your approach will let me get closer to that speed, without that problem. - Don't these boards boot up in a relatively safe mode, and then switch to desired settings once past the bios selection prompt (DEL key)? If so, then my FSB oc problem is a bit odd. - when you say "stock 11.5 multi", do you mean it won't respond to requests for other? or can't be configured for other? - Initially, when toying with the multi settings, I was doing so in case that could get past the 200MHz FSB problem. Was trying very low multi's. Once I get the FSB back to 166, I continued toying with the multi's, and then started this thread. :) I'll give it a go soon... thanks.

With regards to the BIOS "Safe" mode, I had problems like this on my A7N8X, I fixed it with a new battery, as for the Gigabyte boards, I have heard that there are numerous BIOS issues with them, so maybe a BIOS update might help. Either way, you should never make such large jumps. 11.5x is the default multiplier for the 2600+, if you want to test if you can modify the multi's, try using 11x166 (2500+) and see what happens. Something else I should mention is you RAM, if you are running PC2700, you need to know that by increasing the FSB, you are also increasing the RAM speed, thus overclocking the RAM at the same time. Another thing to consider is if you are running dual channel RAM at above 195MHz, you will need to increase your RAM voltage to around 2.7v, regardless of what speed RAM you are using.