I read that the phenom chips will work with most am2 boards.. Does
this include the GA-M55SLI-S4..  I can't find anything definitive, although it looks like the 6400 x2 is almost as fast as the current phenoms.  I want to bump up from the 4400 x2 I have now..
 
Thanks

i dont think its supported.... like people keep saying do a google!!

Just go to Gigabyte's website and look on the CPU support list. I don't even have the board, but I found there are two revisions of the board.  
 
Neither seem to support it with available bios upgrades now, but since there's a listing for the triple core Phenoms (and not the quad core), there might be a bios arriving soon that will support triple and dual core Phenom upgrades.
 
Most motherboard manufacturer's have been slow to get the bios updates out. That's probably because they were waiting on B3 stepping and a full line of quad, triple and dual core Phenoms.
 
Here are the pages:
 
CPU support list for GA-M55SLI-S4 revision 1:
 
http://www.giga-byte.com/Support/M [...] uctID=2310
 
The revision 2 seems to be the same, you can find it yourself on Gigabyte's site using their drop down menu.