Did I do Enough, Could I have done more ?

Dear Wizards,

I performaed my first overtclocking last night:

P4 2.53 with DDR 333, on an MSI 655 Max series MS-6730. (533 Mhz, i.e. 133 FSB, fixed CPU multiplier of 19)

My additional limitation on this (Locked CPU) Ami Bios v3.03, seeemed to be that I could not adjust the PCI/AGP bus freq offset to more than 80/40 (original settings were FSB = 133, AGP/PCI = 66/33), which - given my limited understanding, restricted my reliable overclocking attempts to an FSB of 140 MHz - thus yielding an 2.66 machine (with the corsair memory overclocking reliably at 175 (i.e. 350 Mhz, and with more aggressive timing settings also).

Benchmarking and burn testing shows a reliable 4 to 5% uplift generally everywhere, without hint of instability. All well and good so far.

My questions please:
1, Is my understanding on the FSB-tuning limits imposed by the PCI/AGP offset limit correct generally, and with this board / biosspecifically ?
2, If there is something I am missing that could 'give more go', my objective would be to take it to 2.88 or 3.06 - if stable without fancy cooling.

Many thanks in advance of rall help and advice.

paul.

ByteSize said:

1, Is my understanding on the FSB-tuning limits imposed by the PCI/AGP offset limit correct generally, and with this board / biosspecifically ?

Click to expand...

I think you're thinking of things a bit backwards.

The AGP/PCI frequencies are a funtion of your FSB, meaning they are a direct funtion of your FSB divided by some number. If you put the ratio at 33/66 and your FSB is stock at 133, that divider is 4/2. If you up your FSB with the divider, then the PCI/AGP frequency comes along for the ride: at a 33/66 ratio and 150 FSB, your PCI/AGP frequency would be 37.5/75. If you have the same FSB of 150 with a PCI/AGP ratio of 40/80, then your real PCI/AGP frequencies will be 45/90.

The best thing for overclocking is to lock the PCI/AGP frequencies, so that they stay at 33/66 no matter what you do to your FSB. A lot of PCI devices don't like running out of spec, and HDD data can be corrupted if your HDD is not running at 33 MHz.

Thanks for the help.

successfully running at FSB 145, and PCI back at the regular 33

You're welcome - always glad to help for a better overclock.