overclocking T'birds with a 133 DDR FSB instead of 100 DDR?

[Bignate603]

Ok, i was wondering about how AMD says ou need new prcessors for boards that run on the new 133 DDR FSB (266 effective). Seems to me that you could take an old T'bird, say an 800, (8x100) and adjust the FSB to 133 DDR. Multiplier of 8 times 133 FSB equals 1064. Since most 800s and 750s hit a gig right now this should reach about the same clock frequency without having to draw in the L1 bridges, and give the extra boost from a 133 DDR FSB.

Anybody see anything wrong with this reasoning? People have fooled with FSB overclocking for Intel but AMD boards don't do that well with it right now. This might be another option. To bad nobody has a board to really test this out.

 

[Moonbender]

There is nothing wrong with your reasoning, in fact it is utterly right.
The "old" CPUs have no problem with the higher FSB. Most CPUs up to 800 should work fine without changing the multiplier, and if they don't you can just unlock and lower the multiplier some steps.

 

[Bignate603]

Didn't think of lower the multiplier to find the perfect match... hmm. Oh, and another thought crossed my mind. The board possibly could do higher than 133 DDR FSB, because most boards give you some tweaking leway. That's amazing, multipler overclocking and real FSB overclocking (The little stuff we've done on AMD T'birds doesn't really count) in one chip. You could find the exact max your chip can do.

 

[dougjnn]

Yeah, I get all the bit about working with the FSB x the multiplier on the new Via KT133A boards.

But my question is this. What's the collective wisdom about the bet in a marketed chip speed if you want to try to get to 1.2ghz, or at least 1.1, with a Tbird on a Kt 133A board (running 133 /266 fsb)?

I.e., Amd might do some sort and label its relatively sucky chips down in the 800 area, right? Or is it all totally random, except for testing at the rated speed?

Educated guesses appreciated.

 

[DaddyG]

Both the Soltek 133A mobo and the EPOX version have Oc'ed regular TBIRDS and Durons as high as 150fsb with good RAM. Reaching 133FSB with a regular Duron/TBIRD shouldn't be a big problem except that on higher speed setups, you might have to 'underclock' the multiplier. Its worth the underclock, because FSB Ocing get so much better performance than multiplier Ocing.

BTW the Soltek mobo has an Auto Overclocking feature built in to the BIOS. Just fire it up and the BIOS finds the highest stable FSB, pretty cool.

 

[dougjnn]

I think my ideal theory would be to run the FSB at about 143, to juice the higher return FSB multiplier, but still not run too far out of spec for the PCI boards and all. Maybe just 140.

And then get the rest the chip will do out of the multiplier. Starting by backing it down to about the speed the chip was marketed at, after applying the multiplier to the FSB up at 140. ANd then moving up in .5 multplier steps until flakeyness sets in - and backing off a step.

Well, that's my book learning from reading up on the net, anyway.