For AM2+ AM3 benching, most boards will be fine.

for overclocking nonBE chips you need a AM2/DDR2 board to really push past 50% OC. Biostar has cheap boards that will do it, Gigabyte has some too.

790FX to 990FX I found limited to about 300-315 HTREF clock something like the sempron 140/145 will do that on stock cooler though :)