Played around with my brother's computer the other day (he asked me to try it with his brand new mobo).
Tried overclocking it (ended up not having it oc'd 'cos the mobo didn't have agp or pci locks, and anything apart from an fsb of 166 or 200 wasn't worth it in the end, what with the board being renowned for having instabitility issues with the slightest adjustment of fsb).
Anyhow, tried a few things as you do (multiplier, fsb etc) but I wasn't satisfied, so I ended up downclocking his ram to synch it with his fsb (better bandwidth that way) .
To compensate for the lowered speed I tried making the timings a bit more aggressive. Was careful (or so I thought) but upon the next boot the board (an asus) told me the bios was buggered and asked for a disc with a working bios (it's some fancy-pants function asus calls "crash free bios").
Put the disc that came with the board in (turns out the bios might be one revision earlier, but the subsequent issues aren't covered by the later BIOS anyhow) and it worked on the second try, and it was soon up and running again.
Now everything works just peachy, the timings are good, but not so tight as to cause any trouble, fsb and ram are synched and so forth.
There's one small hassle tho'. The onboard lan is acting up, it works for BT and you can surf with it, but playing CoH or transferring files over the network results in all other computers on the network being cut off from accessing his computer.
Initially it'd disconnect completely after a while requiring a reboot to work again, not directly mind, and before that he'd experience some lagging, but (and I don't know exactly what I did) I managed to change that so it kept connected to the internet, but it'd still cut other computers off, although it could still find them on the network. (The lagging is still there when he plays.)
I played around with it, trying to uninstall it in the device manager, which made the device manager lock up, and I'd try deactivating it, which didn't work too well, and the drivers that came with the board wouldn't install properly.
Windows reports no errors with the card tho', so, as far as windows is concerned there's nothing wrong at all with the card.
And, I downloaded different drivers, and those installed without any issues, tho' it'd still do the cutoff thing.
And a regular pci ethernet card works fine.
The odd part is that it seemed to be affected by how much bandwidth other machines on the network were using, shutting down a couple other computers on the network would make it more stable wrt CoH. It would work with CoH the day before, but we never tried any big transfers.
And previously, this router has acted up, it used to cut another computer on the network off from the others at regular intervals, and it'd be a bitch to access or get to keep rules working, and this kept on happening until the firmware was upgraded. And very recently (with the new firmware) it would cut my brother's computer (with the older mobo) off when he was trying to burn files from his computer in nero on another machine.
So, what is more likely to be wrong, some software or bios thing, the onboard lan, or the router?