Help OCing a Barton 2500+

Okay guys, I need some help here, because this is my first time doing some serious OCing.
Here's what I have:

AMD 2500+ Barton Core (333mhz)
2x256mb PC3200 Kingston DDR RAM in Dual-Channel mode
Asus A7N8X-Deluxe
Retail HSF
3 case fans

Default temp as read in BIOS:
CPU - 40 - 43 C
MB - 21 C (I think)

I have it configured to run at 166mhz FSB and 11x multiplier, and the RAM's at 200Mhz Dual-Channel. Default voltage, 1.65v

Now first, is this the correct configuration? I'm coming from a P3 500 soo...

Whenever I increase the FSB to 180Mhz or higher, the system doesn't POST, and the voice says memory test failed. When I leave the FSB at 166, and raise the multiplier to 12.5x, I get it to run at 2800+, but I have to raise the voltage to 1.75 for Windows to start up... even then, it crashed a couple times, so I switched back.

So what am I doing wrong?!

If you have the same cheap Kingston RAM as me you will probably need to run looser timings.

k, i have no clue about these timings, but they're at
8, 3, 3, 3T

First off do you know what revision motherboard you have? The rev2.0 nforce2 boards oc alot better than the earlier revisions.

When you start raising your FSB there is a couple of things you will want to verify. You want to lock your agp/pci speeds (I cannot remember the exact names of things in the a7n8x bios but there should be an option to set agp speed to 66). If you don't do this then you run the risk of corruption on your HD.

The other thing you will probably want to do is run your memory in sync with your FSB speed. If memory serves one of the bios version for the a7n8x changed the value you need to chose from sync to 100%. Whatever the value is I think the thing you are looking for is called memory frequency. Setting to 100% (or sync) will make your memory run at the same speed as your fsb (if your fsb is set to 133 then its 133x2=266). Its possible that right now it is not set to sync and when you start increasing your fsb you are running your memory out of spec.

Your best bet is probably to lower your multiplier down to eliminate your cpu as a factor. Also relax your memory timings and just keep raising your fsb until you find its limits. After you know your max fsb then start raising mult. You may need to lower your fsb a little to hit your cpu max. You will have to make the judgement call if you want the highest fsb or more cpu speed.

You will need to start raising your vcore when you start ocing the cpu. You may want to just determine what you think the max vcore that your cooling will be able to handle and start there and when you find the limits of your chip lower it a bit.

First thing I would do is get rid of that stock HSF. That will help you out in the long run. Is that HyperX RAM or Kingston value/normal RAM? If so that could be holding you back, try considering upgrading if it isn't HyperX.

Heh I forgot he was running with the stock hsf. Um yeah you won't be increasing vcore very much on that

He doesn't need hyper x to go up to fsb 200. That isn't even pushing PC3200.

Barton retail HSF isn't that bad (my retail HSF is Ajigo)... I lapped and ducted mine and got to 2.33GHz w/ 1.77 Vcore. Although CPU temp was 53°C during Prime95, it was stable...

Have you tried very low multi (like 5) to test the mem and FSB? I would do that first to see how high your FSB can go w/ out CPU being in the equation. There's a guide to do this in the forum somewhere... I'll post if I find it again...