NOTE: please read this whole document before taking any action. I am not responsible for what you do to your system. Note also that some nForce2 boards have a "BIOS Death" but that is caused by overclocking. I personally have never experienced it... but its there. Your risk.
Well, I have been hit up quite a bit either through PMs or through AIM about overclocking, so I decided opening up a thread on it could help everyone. Specifically I have been asked about overclocking AMDs, and even more specifically, it has always been about the A7N8X Deluxe motherboard.
So, feel free to ask questions, and I can help you... just realize the risks involved in overclocking, how easy it is to blow a CPU, that if you dont properly reapply thermal interface material when reapplying a heatsink you wont have the best heat transfer, etc. - any basic hardware questions such as how to apply a heatsink can be answered too
Just to slow the deluge (well... okay... literally only a few, but still, better to start safe than sorry) of posts about how to overclock... here is a simple
Very Quick Guide to OCing an nForce2 System
Alright, first things first. For simplicities sake lets assume you have PC3200 memory. If you have PC2700 memory, you will only be able to go to 166fsb and maintain good performance (going any higher would be a waste), with pc2100 you can only stay at 133mhz FSB and overclock via multiplier. Figure out what kind of memory you have. Again, I am assuming you have PC3200 (DDR400), so if you dont, you're SOL. If you have PC2700, follow the guide to a revision 1 board.
Next, find out what revision of motherboard you have. It should be between PCI slots 2 and 3 on an Asus board, on other nForce2 boards it is in various positions. If it is not a revision 2 from ANY manufacturer, or it doesnt say in manuals / the product name it is an Ultra 400 / 400 chipset, you might not be able to hit 400fsb, and I will let you hit 166fsb - you can go higher if you want to tweak, but for instance my rev 1 A7N8X could only hit 182fsb. I recently swapped it for a revision 2, now running happily at 200fsb, but a known bug limits me from going much higher - though I could if I wanted to...
Third, check out which kind of core you have. Remove your heatsink - carefully! It is all to easy to have a screwdriver slip on ya. Get some rubbing alcohol out and a couplea q-tips while you're at it. Look at the label on the chip... if there isnt one and you see writing directly on the core, you're SOL - put the machine back together, even if you could OC it might not be worth the trouble. If there is a black label that starts with AXDA... but the line below it is something like "AIUGA" where the last letter is A, you're SOL (if it is something like "AXQEA" or "AQZEA" though and ends in EA, you have a Barton, and you can overclock this chip). IF it is something like "AIUHB", you're good to go with a TbredB core, you can OC this sucker.
If you have a 2100+ or higher Tbred, or a 2800+ or higher Barton you will need to remove the CPU and place a wire in the socket in order to allow lower multipliers, and therefore a higher FSB overclock (if you are using an Abit board, disregard this, you dont need to do this). Remove the processor, and place a very small wire, like a strand of speakerwire, in this position:
This will allow 12.5 and lower multipliers, vital to any high FSB overclock.
Now, this is where everything diverges - if you have an Ultra 400 board (revision 2) and PC3200 memory, follow guide #1. If you have a non-Ultra 400 board and/or run Pc2700 memory, follow guide #2.
Note: have a calculator handy.
Guide #1
Use the rubbing alcohol and q-tips on your core to wipe off any thermal interface material. Reapply a very thin layer (as thin as possible) of thermal paste, and make sure your heatsink is clean of any thermal paste/pads. If you dont have thermal paste, go to your local computer shop and pick some up. Apply your heatsink carefully, make sure fan is plugged in and turn it on.
If it doesn't boot up, figure out what you did wrong. If it does, enter the BIOS by hitting DEL a few times.
Go to your respective Advanced Menu (in Asus its over one, down one, in Abit's boards its the first option - SoftMenu III, most manufacturers it is the second or third option down), and pull out your calculator. Take your multiplier and FSB (should be visible on this screen), and multiply the two. Then divide by 200. Round that number up to the nearest 1/2 (so if the answer was something like 12.229038592382, I would round to 12.5), and set your multiplier to that. Set your FSB to 200, and (it might not be in this menu with certain boards like the Abit, you need to go to the real Advanced menu) set memory frequency to "100%" or "1:1" or "Sync."
Save settings, and let it sit there for a few seconds. If it doesn't reboot, clear your CMOS, and if it doesn't post again, you might've been hit by BIOS death (search http://www.nforcershq.com/forum for solutions). IF it does, select a lower multiplier (say I selected 12.5, I would select 12) and try again. If after a couple lowerings it still doesn't want to boot, it could be your FSB. Reset everything and follow Guide #2.
Also, increase your vcore by .5v to be safe - so if it is 1.65v, set it to 1.7v. I can't really advise going over .1v of your setting to anyone around here, since most probably use stock cooling and some use some of the crappier aftermarket coolers. I personally use one of the best air cooling solutions available for the AMD Athlon XP platform to date, and even so, running 1.85volts through my chip can spell disaster. I am taking that risk, but unless you have proper cooling (even if you do, hell), I truly advise you do not run any higher vcore than this. So, to continue...
Boot up (with the assumption that it is Windows). I will need you to download some utilities to see how stable your CPU is and to check temps and speed. Get cpu-z at http://www.cpuid.com, Prime95 at http://www.mersenne.org, and MBM from http://mbm.livewiredev.com. First set up MBM using the motherboard list provided on their website for your motherboard, so you can see the diode temp. It cna be anywhere from 35-60c on most systems. If it is over 50c while you're not doing anything, well... you might want to revert, as thats a bit toasty. For your sake consider anything over 55c fairly dangerous, and anything over 60c unusable.
Next, run Prime95. Select "Just Stress Testing," and select Torture Test in the Options menu. If it fails right away, restart lower your multiplier by .5-1x. Let this run for a few hours, if it doesn't fail, let it run overnight. See how things go. Most likely, this will run through just fine. If it keeps on failing after lowering the multiplier, it could be your memory. Either adjust timings to make them more relaxed, or lower your FSB slightly (do a User Controlled setting if your board supports it, then drop it by just a few numbers). Try again.
CPU-Z is just there so you can see how fast your system is going. If you notice your FSB jumping lower (like me, I would run at 202fsb, it would go from 200-202fsb) there is a problem and manually lowering your FSB by 1mhz or so often fixes this problem.
If all is well after overnight of Prime95 (icon still red, no errors) and temps are acceptable, you have a good overclock already - evne though you aren't much faster, if any faster in mhz. The FSB is important, and you will notice greater speeds. if you ahve very good PC3200, you can try raising the FSB more, or you can raise the multiplier and re-test in Prime95 until you are satisfied with speed/heat/stability.
Any more questions, just ask.
Guide #2
Note: if you have a barton, this guide is useless, unless you want to follow the advice to use a higher multiplier. You could try slightly raising the FSB, but that is beyond the scope of this document...
Use the rubbing alcohol and q-tips on your core to wipe off any thermal interface material. Reapply a very thin layer (as thin as possible) of thermal paste, and make sure your heatsink is clean of any thermal paste/pads. If you dont have thermal paste, go to your local computer shop and pick some up. Apply your heatsink carefully, make sure fan is plugged in and turn it on.
If it doesn't boot up, figure out what you did wrong. If it does, enter the BIOS by hitting DEL a few times.
Go to your respective Advanced Menu (in Asus its over one, down one, in Abit's boards its the first option - SoftMenu III, most manufacturers it is the second or third option down), and pull out your calculator. Take your multiplier and FSB (should be visible on this screen), and multiply the two. Then divide by 166. Round that number up to the nearest 1/2 (so if the answer was something like 12.229038592382, I would round to 12.5), and set your multiplier to that. Set your FSB to 166, and (it might not be in this menu with certain boards like the Abit, you need to go to the real Advanced menu) set memory frequency to "100%" or "1:1" or "Sync."
Save settings, and let it sit there for a few seconds. If it doesn't reboot, clear your CMOS, and if it doesn't post again, you might've been hit by BIOS death (search http://www.nforcershq.com/forum for solutions). IF it does, select a lower multiplier (say I selected 12.5, I would select 12) and try again. If after a couple lowerings it still doesn't want to boot, you might just be out of luck, or you could be trying to OC that Palomino processor like I told you not to sorry.
Also, increase your vcore by .5v to be safe - so if it is 1.65v, set it to 1.7v. I can't really advise going over .1v of your setting to anyone around here, since most probably use stock cooling and some use some of the crappier aftermarket coolers. I personally use one of the best air cooling solutions available for the AMD Athlon XP platform to date, and even so, running 1.85volts through my chip can spell disaster. I am taking that risk, but unless you have proper cooling (even if you do, hell), I truly advise you do not run any higher vcore than this. So, to continue...
Boot up (with the assumption that it is Windows). I will need you to download some utilities to see how stable your CPU is and to check temps and speed. Get cpu-z at http://www.cpuid.com, Prime95 at http://www.mersenne.org, and MBM from http://mbm.livewiredev.com. First set up MBM using the motherboard list provided on their website for your motherboard, so you can see the diode temp. It cna be anywhere from 35-60c on most systems. If it is over 50c while you're not doing anything, well... you might want to revert, as thats a bit toasty. For your sake consider anything over 55c fairly dangerous, and anything over 60c unusable.
Next, run Prime95. Select "Just Stress Testing," and select Torture Test in the Options menu. If it fails right away, restart lower your multiplier by .5-1x. Let this run for a few hours, if it doesn't fail, let it run overnight. See how things go. Most likely, this will run through just fine. If it keeps on failing after lowering the multiplier, it could be your memory. Either adjust timings to make them more relaxed, or lower your FSB slightly (do a User Controlled setting if your board supports it, then drop it by just a few numbers). Try again.
CPU-Z is just there so you can see how fast your system is going. If you notice your FSB jumping lower (like me, I would run at 202fsb, it would go from 200-202fsb) there is a problem and manually lowering your FSB by 1mhz or so often fixes this problem.
If all is well after overnight of Prime95 (icon still red, no errors) and temps are acceptable, you have a good overclock already - evne though you aren't much faster, if any faster in mhz. The FSB is important, and you will notice greater speeds. if you ahve very good PC2700 or higher, you can try raising the FSB more, or you can raise the multiplier and re-test in Prime95 until you are satisfied with speed/heat/stability.
Any more questions, just ask.
