DaveDDS wrote on Yesterday, 20:41:

Curious how you arrived at this? (I don't have a lot of experience with Athlons) […]
Show full quote

pete8475 wrote on Yesterday, 03:58:

Well that would be because the KT133 chipset does NOT support 133FSB. ...

Curious how you arrived at this? (I don't have a lot of experience with Athlons)

I don't see "KT133" within the original post.

The CPU specs page linked in that post says "AM1400AMS3C" and says it supports 200mhz bus.
The mainboard link also says 200.

The wiki page you pointed to doesn't show bare "KT133" and other KTs go above 133.

Just curious - would like to understand Athlons better (I have one somewhere in a box - If I ever find a board that it works on I'd like to bring it up)

Well KT133 is the chipset used on the board OP has.

That chipset does 100MHZ FSB (aka 200 in AMD speak). The Athlon XP processors use a 133 (266 in AMD speak) FSB speed, even later Athlon XP processors have 166 (333) or 200 (400) FSB.

A lot of things in that era got weird when AMD started using model numbers like 2400+ instead of MHZ numbers.

EDIT - also in the wiki page KT133 is listed as Apollo KT133.

Good to know - I hadn't noticed the "Chipset KT133" in the board page (to be fair I didn't spend a whole lot of time on it, and since KT133? were on the CPU page I didn't really expect to see one there)

And "FSB 200" is confusing since that's faster than what the OP was trying to reach - but once you look into dividers it makes sense (and I never liked AMD's practice of "we think it is just as fast as ..." to spec CPU Speeds)

Thunderbird 1200B should work. Or 1400 at 100mhz fsb after pencil multiplier unlock to set 14x. Not sure if kt133 allows multiplier that high.

From a plug and play perspective, you are limited to something with up to a 12.5x multiplier unless that particular CPU uses a ‘cheat’ to give a higher multiplier. The 1400B does this, as does the 2100+ palomino. A 2100+ palomino should run at 1300MHz on a KT133

Beyond this you can modify the CPU socket to unlock multipliers 13x and above. You could run a 2600+ Barton at 19 x 100 for example. There are various threads and guides detailing this.

I would expect a later Athlon CPU to not be recognised, but it’s possible to modify the bios to get it to recognise the CPU. Again there are videos on YouTube by necroware and bitsundbolts about patching a bios to add additional CPU support

Of course it takes some work to make these alterations and if it’s never been done on that board, there’s no guarantee it’ll work. I did all of this with a KT133A board (near-identical chipset, which can do 133MHz FSB) but I was not able to get the board to run stably at the FSB x Multi I wanted. It did run fine at 100MHz FSB though with the modification. I think I ran it as high as 2300Mhz in this configuration. The absolute max is 24x