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View Full Version : How to change FSB:PCI ratio? Oh and AGP too



george12
30-10-2004, 08:51 PM
Hi there.

I have a Celeron D 2.4GHz cpu, about 2 weeks old.

I have it overclocked, running at 3.06GHz (170MHz fsb). The DDR ratio is set at 1:1, so my DDR400 ram runs at 170MHz = DDR340.

But I can't seem to find a way to change the PCI ratio. It seems locked at 4:1, ie. 133MHz FSB = 33MHz. So when I change the FSB to 170, the PCI is at 42.02MHz, when it could be at 34MHz if I could change the ratio.

Same thing with AGP, it's running at 84MHz (shows in software as 336MHz but I think the integrated graphics is AGP 4x so it works out).

So how can I change these two? I have looked everywhere in the BIOS, and besides I know it must be possible because if you stick in a P4 with an 800MHz FSB it will run the PCI with a 6:1 ratio.

Thanks,
George

george12
30-10-2004, 08:52 PM
Oh and BTW, if I run it past 3.4GHz it just instantly reboots. But that's not really the point, it's more that I would like to protect my precious PCI and AGP stuff.

Prescott
30-10-2004, 08:56 PM
might depend on what mobo you have...
the feature is in the bois and you can lock the agp and pci speeds, not sure how it exactly worded/looks like cos i dont have that feature :( so hence no oc for me :(

george12
30-10-2004, 09:13 PM
Well, I don't seem to have it either. But surely there is some way that it could be changed.

For example, the same thing that makes it decide whether you have a 400, 533, or 800 MHz FSB CPU could surely be changed somehow?

Some expert here must know I'm sure.

George

Spacemannz
30-10-2004, 09:19 PM
For example, the same thing that makes it decide whether you have a 400, 533, or 800 MHz FSB CPU could surely be changed somehow?

I wld say this would be in the code of the BIOS.

If the mobo and CPU match it would change things in the BIOS.

eg: For HT if the speed of the CPU is the right speed for HT, the BIOS will give u the option of enabling/disabling HT. If NOT then the BIOS wont give u the option for HT.

Prescott
31-10-2004, 10:42 AM
say if there was a BIOS update, would this unlock new features? like overclocking features or the pci/agp lock?

Big John
31-10-2004, 10:55 AM
Try hitting Ctrl-F1 when in the BIOS main menu and you might get some advanced options. I know this works in my MB and BIOS. The change might not look like anything happened but check out the sub-menus and see if it opened any new doors.

HadO
31-10-2004, 11:25 AM
In my BIOS there is no option for locking - the AGP and PCI bus speeds are just locked by default - overclocker friendly :D

There is an option for memory speed which translates to FSB:DDR ratio though.

I was overclocking with an old board with unlocked AGP and PCI and never really got any major issues - only thing was AGP card rebooting system if the CLOCK rates were adjusted too high...

I suppose its just a matter of luck and the amount and price of AGP and PCI devices in your system... your decision.

Go get a overclocking mobo if you concerned or run at stock speeds!

Prescott
31-10-2004, 09:30 PM
> Try hitting Ctrl-F1 when in the BIOS main menu and
> you might get some advanced options. I know this
> works in my MB and BIOS. The change might not look
> like anything happened but check out the sub-menus
> and see if it opened any new doors.

i dont think this worked for me, i was hoping to have some oc features but i cant seem to find it.........

Pete O\'Neil
01-11-2004, 08:33 AM
Ctrl + f1 only works on Gigabyte boards, they hide all the settings that allow you to damage your hardware.

george if your BIOS doesnt allow you to set the PCI/AGP frequencies then there ant alot you can do. Possibly look for a 3rd party BIOS but with a motherboard as obscure as yours its like looking for a needle in a haystack. You could learn how to code your own BIOS and then modify the BIOS yourself, but the chance of the motherboard even being capable are slim.

I hate to say it but you get what you pay for. Theres a reason overclockers buy the more expensive boards.

Prescott
01-11-2004, 04:38 PM
where can i get these 3rd party bios? are they any good? im gonna check google now.....

Pete O\'Neil
01-11-2004, 04:45 PM
Best try google, for an Intel board its like looking for a needle in a haystack, very very few exist. And the ones that do exist are often not worth having. AMD on the other hand have a thriving third party BIOS community offer BIOS for most boards ;).

Prescott
01-11-2004, 04:49 PM
whoosh.... there go my chances out the window...... :p