Your motherboard doesn't officially support an XP-M but it should work. (Very few desktop motherboards have native support for laptop CPUs.) Don't worry about the Barton core; in fact be glad that it has the extra cache!
After a proper installation of the CPU and HSF, your main concern will be manually changing the multiplier. At the first POST the system will probably come up at 6 which times 133/266MHz will only give you about 800MHz. You'll have to increase the multiplier via your BIOS or a wire trick or Windows software. Hopefully your BIOS allows manual changes as that's the preferred solution.
If your RAM and the rest of your system allow you to increase the FSB definitely look in to that as well. 166 times a slightly lower multiplier usually is better than 133 times something higher because the RAM is running faster. (IE: 200x10 is faster than 166x12 while both are faster than 133x15 - even though they all give an overall speed of about 2GHz.)
K8N Neo2, Opteron 180, 2GB G.SKILL PC3200, 9600XT, Cooler Master CM 690/RP-600-PCAR
GA-K8NS Ultra-939, Opteron 175, 1GB PNY Verto PC3500, 9600XT, CM Centurion 5/RS-450-ACLY
A7N8X-E Deluxe, XP-M 2600+ @218x11, 1GB KVR PC3200, 9550, Lian Li midtower/RS-450-ACLY
AN7, XP-M 2800+ @218x11, 1GB HyperX, AIW 9600XT, Antec Super LB/TPII Blue 480http://classicplatforms.com
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