333 FSB on a 266 FSB AMD...


OSNN Senior Addict
Hypothetically, what is the limiting factor if I try to run an XP2000+ at 333 FSB instead of the 266 FSB it is designed for (assuming I had a mobo that supported it)? I do not mean the memory bus, I mean the FSB of the CPU itself.

I ask this because my old processor, a 1GHz T-bird was actually a 200 FSB processor (100 x 10 multiplier), but I simply upped the bus to 266 which made it a 1.33GHz (133 x 10 multiplier). It has been running fine like this for over a year and runs at about 40-41 deg C idle on a stock HSF (actually its using the HSF from the XP2000+).

I know the mobo in my sig doesn't support those CPU's (yet), but possibly a future BIOS update may fix that. If a BIOS update does become available someday to support a CPU FSB of 333, that would be nice so the mem can run syncronous with the CPU. I figure the XP2000+ is so cheap these days, it's almost worth a try :)

Technically, going from 200 to 266 is a bigger o/c than going from 266 to 333 (percentage-wise).


Yeah it will work, put a better heatsink on it though, I recommend one of the coolmaster heatpipe heatsinks, maybe a little more vent in the case but it should be fine.


hardware monkey
the fact that you were able to get your 200fsb athlon up to 266 is luck, i'd have to say. i haven't heard of anyone else getting away with that.

my friend has the same processor, though... maybe once he gets a new mobo, we'll have to give that a try. }:>


F@H - Is it in you?
Staff member
Political User
actually going from 200-266 is only an oc of your fsb of 33 points.. I mean still it is a BIG amount but I cant' see you doing the same to a 2000+ XP cpu...

more than likely if you don't burn something out you will get compatability issues...

frankly speaking... you CAN run a 333fsb cpu on most of the newer 266fsb mobo's... they might even be able to RUN the cpu with 333fsb... I know that some of the MSi boards are designed to do this... therefore some of the other good mobo's should be able to as well..

now one thing to remember.. whenever you are oc'ing TRY and keep the Pci clock under 40mhz...


hardware monkey
a 33% (200-266) overclock without an increase in voltage is quite impressive. especially since it's done without unlocking the processor and instead done solely with the fsb.

going from 266-333 is only a 25% increase, so maybe it's attainable. but i'm thinking with the newer athlon xp's (eg, 2000+), they're already pushing the envelope of their architecture and probably won't give you that much overclocking room. and i'm not sure if you can damage your processor or board by trying.

leebobs... i don't mean to challenge your intelligence, but are you sure your processor isn't a 1.33ghz (133x10) at heart? have you seen the numbering on the die itself? just curious.


OSNN Senior Addict
taurus: I thought it was lucky too. I didn't even have to change the voltages or anything and it stays pretty cool (40-41 @ idle). The funny thing is the board came that way. I had ordered a 1Gig t-bird with the mobo (a gigabyte GA-7dx) from TCComputers and they put it together and test it for you. Well, I opened the box, stuck it in my PC and booted up. Well, the BIOS said 1.33 and I thought "Cool, they gave me a better CPU!". But when I remounted the CPU/HSF, I read the die and it was "only" a 1Gig. Since the board supported the 133 FSB, the PCI was at 33 and the AGP was at 66. I have even pushed it to 138 FSB, which gave me a 1.38 CPU!! But it got too warm on the stock AMD HSF I had so I backed it down. Either I got a really nice CPU or those t-birds are tough.

Sazar: Yeah, I know about the PCI/AGP ratio. Thats the part that kinda sucks about my current board is that I know it wont have a 6:1 divider for the PCI, unless they release a BIOS for it. I was mainly just curious since I pushed the old CPU so far. But my current mobo/CPU was cheap (about $200 for both) and will last about 6-12 months until I see how the Hammer fares :)

Since that t-bird is so old, I thought about unlocking it (temporarily using a pencil) and setting it to 12.5 along with upping the FSB to 133. That would take it to 1.66, a 66% increase from Stock! Hell, if it burns out, I can just replace it with a cheap 1800+. Those are only like $80 now.

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