Overclocking

[bids]

Have a bit of a weird problem - dunno whether anyone has any ideas.

My younger bro has my old Chaintech 6BTM motherboard, and 'cause his Geforce DDR went tits-up he bought a Radeon 64 DDR. With the Geforce, the FSB was overclocked by 12%, and with the extra cooling was rock stable under XP. However, since putting the Radeon in, we can't overclock the bugger at all - locked FSB at 100 Mhz. Tried SoftFSB with no effect.

Anyone have any ideas / things to try (apart from changing the video card before anyone goes down that route )

 

[Xavier]

can you tell us a little more about the system... cpu/memory etc?

also - what bios revision is the motherboard on?

Cheers,
Xav

 

[bids]

CPU is PIII 800 Mhz with duel fanny thing to keep cool - will run at c. 900 no problem with the Geforce.

BIOS revision is most recent revision for the Chaintech 6BTM (5.05 iirc) - memory is generic 100 mhz 4x128 Mb - also runs fine at 112 Mhz with the cooling / Geforce.

Thnx in advance Xavier

 

[Xavier]

it's extremely unlikely that the memory is bailing, but 10% over spec (110Mhz in your case) is the average limit (some people do manage much more)

As the system was fine with the Geforce all I can think is that the ATI is proving very sensitive to the increased AGP clock it's running at...

Normally the AGP is 66Mhz, anything quicker than that is quite literally 'out of spec' although many cards can cope with clocks in the 80's (more luck than anything else)... on a 100Mhz fsb it uses a 2/3 divider to determine it's mhz frequency - 2/3*100 = 66Mhz

at 112Mhz that's only 70Mhz but it has been known for such small differences to cause problems, for some reason especially on Intel chipsets (a pity as they're otherwise top pieces of kit)

I'm betting that if you dropped a Geforce, or for that matter maybe another ATI into the AGP it would run fine, it may well be that you've just been unlucky and have a card that is particularly sensitive to the AGP clock...

You can try dropping the agp to 2x and updating the bios which might resolve matters but I wouldn't hold my breath... If you can't get the memory back up to 112Mhz you could always switch it's latency to cas 2 (it should cope) which will give at least some extra oomph!