The m chips are identical to the non m. They just managed to run stable at a lower voltage.

Ie, they are better quality at the silicon level.

It's a 5% clock boost for and a larger cache.
I see no reason it wouldn't work. It may not display the "correct" name, though.

i bought the exact same cpu, but did not have any luck with my iwill kk266plus. i subsequently discovered the board will not recognize ANY thoroughbred/barron core. i settled on a palomino 2000 mp. i can clock it as low as a 5x multiplier, but i don't get the on-the-fly adjustments via cpuspd (or as low as a 3x multiplier) that a true mobile cpu has.

don't let me dissuade you though. if your motherboard already supports a thoroughbred/thornton, i don't see any reason why a mobile barton wouldn't work (especially an fsb266 desktop replacement designated one). if you have a mind to you can easily patch the cpu microcode in your bios to properly recognize the cpu.

i'm hoping the AXMA2800FKT4C will work in a biostar m7mia (amd760 with ddr), but that board abruptly stopped working. i'm assuming bad caps so i'll try the cpu out sometime down the road when i find someone to do the repair. i know this cpu WILL work in a later revision abit kt7a so fingers crossed.

I received and installed the Athlon XP-M 2800+ AXMA2800FKT4C processor. The BIOS isn't recognizing it properly, and I can only manually set it to a 12.5 multiplier, which then runs at 1667 MHz. Does anyone know what I can do to get it to run at a 16 multiplier? My old processor, the one I originally installed, was an Athlon XP 2400+ AXDC2400DKV3C with a 15 multiplier. I'm running BIOS 1012; there's still a beta version, 1013.001. Can I install it without any issues? It's half the size of BIOS 1012 and has a different file extension.

Can anyone help me solve this problem?

Looks like it's official on site. https://www.asus.com/me-en/supportonly/a7a266/helpdesk_bios/ Should unzip to 256k, same size as the others
https://theretroweb.com/motherboard/manual/a7 … e3644582045.pdf - The jumper / jumperfree settings might be worth a look, maybe try jumper mode, set 133/133 on DSW1-4 and DSW 10 to off (no manual selection) - however, it seems the XP-M has a 5th multiplier bit, so that may still be tied
CPUMSR might be another option, can alter XP-M multiplier on the fly - only possible link I found https://community.hwbot.org/topic/92747-old-s … clocking-tools/ - the link from there is live, but very much at your own risk, cannot vouch for authenticity or safety

This was the trick to get higher multipliers with the XP-M. If you zoom in on the photo you can see the small piece of wire dropped into the socket.

https://www.overclockers.com/forums/threads/s … d-above.279392/

Repo Man11 wrote on 2025-08-08, 20:11:

This was the trick to get higher multipliers with the XP-M. If you zoom in on the photo you can see the small piece of wire dropped into the socket.

https://www.overclockers.com/forums/threads/s … d-above.279392/

Thanks very much for your advice. The trick with the wire worked with my Athlon XP-M 2800+ 2133mhz AXMA2800FKT4C. I can now set a multiplier from 13 to 18. However, I can't get my processor higher than 15. If I set it to 16, my PC won't boot. Increasing the voltage didn't help either, unfortunately. Is there a way to get this processor to a multiplier of 16? The processor is also displayed incorrectly during the post. The post says it's running at 1800MHz. See my picture.

Could this perhaps be fixed with a microcode update so that the processor name and MHz are displayed correctly during the post? And if yes, do you or anyone know how that has to be done?

The BIOS Patcher could (potentially) solve your issue, but you have to be careful because it can easily result in a board that won't POST. No big deal if you have a chip flasher or are wiling and able to do a hot swap BIOS flash.
https://www.youtube.com/watch?v=0KBYj1vx3zQ

stanwebber wrote on 2025-07-31, 14:30:

i bought the exact same cpu, but did not have any luck with my iwill kk266plus. i subsequently discovered the board will not recognize ANY thoroughbred/barron core. i settled on a palomino 2000 mp. i can clock it as low as a 5x multiplier, but i don't get the on-the-fly adjustments via cpuspd (or as low as a 3x multiplier) that a true mobile cpu has.

don't let me dissuade you though. if your motherboard already supports a thoroughbred/thornton, i don't see any reason why a mobile barton wouldn't work (especially an fsb266 desktop replacement designated one). if you have a mind to you can easily patch the cpu microcode in your bios to properly recognize the cpu.

i'm hoping the AXMA2800FKT4C will work in a biostar m7mia (amd760 with ddr), but that board abruptly stopped working. i'm assuming bad caps so i'll try the cpu out sometime down the road when i find someone to do the repair. i know this cpu WILL work in a later revision abit kt7a so fingers crossed.

For XP-M I'd recommend KG7-RAID. I installed a 2400 in mine and with a X800XTPE that thing is blazing fast.

i used the rom.by bios patcher to patch the cpu microcode:

https://vogonsdrivers.com/getfile.php?fileid= … 904&menustate=0

there are newer versions around, but i don't see any benefit for our boards. the process should be risk-free as it flashes a recovery process (via keyboard press) that will boot the original unmodified bios. after successful testing you can flash the bios again with the recovery option disabled (/s switch if i remember). in fact, if you have a usb keyboard the original bios might always boot by default until you disable the recovery option. don't rely on my memory...make sure to view the readme.

my iwill kk266plus tops out at 13x (or maybe 14x). there are options in the bios up to 15x, but selecting those just boots it with a way lower corresponding multiplier. if you have a true mobile cpu (unlike me) i should think cpuspd or setmul can modify the multiplier higher after boot.

I ran the BIOS patcher on BIOS version 1012 of my A7A266.
See my picture below.

Did I run the BIOS patcher correctly? Could someone please explain to me what the messages 1, 2, 6, and 11 mean?

that's not the output i got from my award bioses. it doesn't look like the cpu microcode got updated. i had heard that asus re-authored their bioses in-house while pretty much everyone else just used what award engineered. maybe that's what you are running into here. i've never owned an asus board. this will require more research.