I have a Biostar (GeForce 6100 am2 (v1.x)) motherboard. I don't know whether it supports ASPM or not, but I wouldn't hope for them to release a BIOS that did. It works alright, but it has it's quirks (suspend isn't quite what you'd expect, and it displays a warning at every POST if you upclock anywhere beyond the base 200Mhz...whatever that means; actual processor speed doesn't seem to change).
They haven't updated the BIOS for this board since December 2007, and it was a beta version. Of course, the 3.x revision of the motherboard has a more recent (not beta) BIOS, but I dare not try to use it on my board....
Lessons learned: do (actual) research before you buy, and don't buy cheep. >_<