HELP!!! with C/Cing a Cel400 - how does volt. work with mult. & freq.?



New Member
I've got a Celeron 400 on an ASUS P3B-F mobo (jumper-free rules!!) and before I get myself into trouble, I need to know how the voltage setting works with the multiplier and frequency settings.

I gather that with a Celeron 400 the multiplier is locked so I have to leave that alone and try messing with bus speed - TRUE? If I do how will that affect other hardware?
Hardware installed:
Celeron 400
ASUS P3B-F mobo
128MB PC-100 RAM
3dfx Voodoo3 2000 PCI 16MB
Diamond Monster MX300 Sound
Western Digital UDMA/33 10.1 Gig HDD
Acer 50x CD-ROM
Some off-brand 2x2x6 CD-RW

Also, how does the voltage work into all of this?

Any cooling suggestions?

Any help will be greatly appreciated.


New Member
I would need an egineer to explain why voltage tweaking works, but I know from personal experience, it does..

Here's how you do it..

The default core voltage for all Celly's is 2.v...

Start there (2.v), and start raising your FSB ...

If you cannot get stability at a particular FSB try raising the voltage a tenth
or less, if possible..... More voltage generates more heat... (much more so than raising the frequency)..
So you have to pay attention to your cooling...

It is probably not a good idea (IMHO) to raise the voltage above 2.3v .....

That's about it... Let us know how it goes...

P.S. Voltage is probably not an issue at FSB's below 100... You have to worry about PCI device problems..
So, I would not start raising the voltage until I was working with 100 and beyond..


New Member
Check and see if your motherboard has an FSB setting that says "92 (1/3PCI)". This is the easiest, most trouble-free overclock you'll ever do if you have an FSB setting around 90mhz AND a 1/3 PCI clock divider. Almost any C400 will run on a 90mhz bus speed, and your PCI bus speed won't stray too far from 33mhz. You are fortunate to have the PCI version of your 3D card, its difficult to get an AGP card to operate on a 90mhz speed. you'll need a AGP clock divider setting in BIOS that says "2/3" if you ever buy an AGP type card.
If you didn't already know this, the multiplier settings you're seeing are worthless. It won't make any difference what the multiplier is set to in the BIOS, because Intel has locked the chip at a multiplier of 6, and you cannot change it. The Celeron will ignore any attempt to adjust the multiplier. Changing the FSB speed is the only way to overclock. So, if you set the FSB to 92(1/3PCI), it will result in a 552mhz Celeron that's equal in performance to a P3-500. It will run a bit hot, especially if you raise the core voltage to 2.2volt or higher, so be careful about the CPU temp while you're doing all this. If your CPU temp gets near 140F, like mine did, you'll need to find some way to cool it down. A big heatsink should work pretty good.I added a case fan blowing onto factory Intel heatsink and removed the side panel fom the computer, my CPU temps looked a lot better after that. It won't hurt nothing to try the 100mhz FSB setting, if you can run stable at 600mhz with a core voltage of 2.3 or less, get a big heatsink and enjoy your kick-ass machine. Email me with any questions, but I'm not familiar with ASUS motherboards.