Whats holding me up?

[zeus]

Ive been overclocking my cpu for a while now but struggle to get passed a certain speed.
Ive got a P4a, PC100 and an Asus P4B.

I can overclock with bios or jumpers.
If I use the jumpers I can change the fsb:pci ratio, but I cant up the core voltage.

If I use bios I can change the vcore, fsb, fsb:mem ratio fsb in 1mhz.


I use the bios to overclock as I need to increase the vcore to 1.55-1.6v to get passed 110 fsb.
I get to 120 (2.4ghz) fine but stability slowly decreases untill I reach 127mhz (2540mhz) where it wont pass post.

So what I do is get some pc133 and start at 120mhz. But I have the same trouble with stability. Kinda telling me it isnt my RAM failing me.

Id check the fsb:pci ratio next but cant because I need to use the jumpers to do so, but cant get passed 110mhz because of the core voltage. (How safe is the voltage fix? You know when you wrap wire round specific pins? I try most things but this seems dodgy.)

So im stuck at about 122mhz fsb (stable).
Its not the ram cos PC133 @122 doesnt help.
Its not the voltage
Im confident its not the CPU. It quite often reaches 2.6 (133 fsb)
Its not the board (most max at 142mhz)
so it leaves what? The pci port?

Does anyone know at what speeds the pci and agp ports max out at?

If its safe Ill do that voltage fix and use the jumpers, giving me a max fsb of 133, (2667mhz cpu).

Or am I barking up the wrong tree? Could it be the cpu? The temp is low.... usually say 50c @ 2.5 and about 1.65v.

Cheers dudes.
I know I have an nice overclock already but the RAM can go further (especially when I havent even started to use the pc133), the cpu is a great overclocker, as is the board.
Like I said.... Im stuck!

 

[Big B]

The temp looks good. The voltage you don't want to go over is 1.7V. After that you start to risk killing your CPU through over volting it.

It's not so much the PCI or AGP slots as much as the cards that are in them. The PCI frequency that you'll probably start running into trouble is 40MHz.

I would suggest downloading and running Prime 95 for 24Hrs and seeing how that runs. If it runs at X speed for 24 hours, your system is considered stable at that overclock and voltage.

Also consider that your CPU may simply not be able to go any further. If you've been able to run it in another board and successfully clock it higher, we'll talk.

From experience, just because joe schmoe hit's a certain FSB or overclock doesn't mean you will. Too many factors exist in overclocking. You may simply be the odd man out with a lower OC.

 

[zeus]

Ok cheers for that.
When I get this Abit IC7 for my mate Ill throw the cpu in and see if it makes the 533 bus. If it doesnt.....

 

[zeus]

Well I had another go today.
I managed 130FSB. Thats with the core voltage at 1.7v. The RAM was at 130mhz and still at quickest latency settings.
It completes Sandra and 3D Mark 2001 with really nice scores. I actually beat a P4 2.66ghz with my 2.6ghz with pc100.

My 3d mark swent from 3000 standard to 3800.
I can make just under 5000 but thats overcloking it from 250 to 330 on the core and 166 to 210 on the sdr ram, with a cpu at 2.4 from 2ghz.

When I overclocked the gpu core to summit like 290-300 (cant quite remember now) it crashed.

I feel still the cpu will go the way, it stays really cool even with the standard hsf. The pci bus and the RAM has gotta be holding me up now. I removed the souncard to try n go further but it didnt help.
Im gonna try it with 128mbs of pc133 next, see if I can go any further.
Im considering the P4 voltage blag now, I can have a 1:4 pci:fsb ratio then.
This RAM though is doing really well. It is giving 1gb bandwidth now, compared to the capped 650mb ish at normal pc100 speeds.

2.6ghz from a standard cooled P4a 2ghz with PC100 has put a smile on my face!

It passes POST at up to 137mhz fsb! Just hangs when loading windows at anything above 132mhz. Consistent boots too.

Im gonna end up blowing this thing up before I stop overclocking :D