Don't get bogged down in the specifications of the two CPUs; what really matters is that high locked multiplier. More than one person has pointed out in your other post, 12.5 is going to be difficult to run at FSB 200. I know you're in a bind because you want to find a good CPU but the odds are more in your favor if you find one with 11x or 11.5x.
No matter what the advertised wattage or amperage, most XP2800+s would have no problem running at the XP3200+'s 11x200 - IF YOU COULD CHANGE THE MULTIPLIER FROM 12.5 TO 11.
If I remember correctly from a couple of years ago, increasing the FSB from 166 to 200 to overclock an XP2500+ didn't raise the CPU temp very much. I think it went up a couple of degrees. But I did have to increase vCore to make the overclock stable and that added a few more degrees.
K8N Neo2, Opteron 180, 2GB G.SKILL PC3200, 9600XT, Cooler Master CM 690/RP-600-PCAR
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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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