AM2 upgrade to Phenom?

A mate of mine has an older AM2 board m2n SLI Deluxe and wants a faster processor and upgraded graphics for games.
Now I know the board supports most of the existing AMD processors but how much will a faster processor be held back by the slower HT link of his chipset?
Should I advise a switch to an AM3 board and processor.
Yes. Money is tight:(
 
Phenom I's are officially supported
though ive looked it up and the phenom II x4 940 BE works in the board (though, i don't think that it will OC well from what ive read)
also, i have lost the link since i sold that computer to a friend

i suggest the board i have M4A78-E, it works with the new Phenom II (AM3 or AM2+) and uses DDR2 memory so he wouldnt have to buy new memory for an AM3 board (uses DDR3), as a plus, if you need to upgrade the bios, you can use the cpu from M2N SLI Deluxe