Does ASUS M5A88-M Motherboard supports 45nm CPUs?

Yes. AMD Phenom II are 45nm and are supported on this board. So to speak this mobo supports "AMD AM3+ FX™/Phenom™ II/Athlon™ II/Sempron™ 100 Series Processors".

Here is the CPU support list for M5A88-M
ASUS - Motherboards- ASUS M5A88-M

thanx a lot.

Always see the supported CPU list along with BIOS rev.