How to lock PCI/AGP bus: MSI 875p FIS2R ?

Hey all,

I've successfully been able to OC my P4 3.0c stable to around 3.6, but I'm worried about my PCI/AGP peripherals running at those FSB frequencies, so I've stepped back to stock FSB for now.

I need to know how to "lock" the MSI 875p FIS2R PCI/AGP bus at 33.3/66.6 (or a desired frequency) if it's even possible with this BIOS. I've looked everywhere, and as far as I can tell so far, the PCI/AGP bus has only one choice: to ride along with your FSB setting. Am I totally missing something?

My other board: ASUS P4C800E-Dlx has a simple setting to lock in the PCI/AGP bus desired frequency. I've heard the MSI board can do it, but I have yet to find out how.

Any help is greatly appreciated before I pull all of my hair out!

Thanks
-HiAmp

Answer from MSI Support

" You can do it with MSI’s Core Center utility:

Sincerely,
Technical Support Division
MSI Computer Corp.
http://www.msicomputer.com "

OK, so I can only assume (since no additional information was offered and Core Center doesn't have an AGP/PCI frequency adjustment) that when you use the Windows Based Core Center utility, the FSB of the PCI/AGP bus is not changed along with the FSB of the CPU. That's good news, if it's true.

Keep keepin' awn!

-HiAmp

HiAmplidude .I do not have a 875 board but here is how I did it on my 865pE

Go into bios ,
then "Frequency"
set your FSB to where you want it, the AGP/PCI will rise as you raise the fsb .
Then just drop down to the PCI/AGP bus and change it.
It will not let you set it too 66/33 but it will allow you to get close . My bus is set at 67/64

I don't like using core center as I obtained better overclocking results using the "Bios"

I hope this helps

Dave

Dcasole, you da' man!

I guess I must have been in slacker-mode because I hadn't even tried to change the PCI/AGP bus after changing FSB! When FSB is at default, the PCI/AGP bus is grayed out and can't be changed. BUT!... when the FSB has been changed in the BIOS, suddenly the PCI/AGP bus frequency can be manually changed. This is EXACTLY what I was looking for.

Thanks for opening my eyes! I wouldn't have even thought of trying that without your post. I'm back to 3.6 stable on air (even in Far Cry)!!!!!!

HiAmplidude, i take it that your not running any s-ata drives?

the reason i say this, is that if you enable the sata ports on the intel ich5 controller, it locks the agp to 66/33.

this works for everyone as far as i know. give it a go and report back what you see

Hey.. I didn't know that (about SATA locking the AGP/PCI bus)! Good to know!

Nope... I'm running SCSI U/320 RAID-0 with a single ATA133 drive on the Promise channel for the pagefile. Disk I/O is smokin' fast!

hehe yeah, its another one of those MSI bios quirks.

works like a charm though