Compatibility issue or bad ram???

That is the question. i am having trouble determining this.

I have the supermicro p3tddr motherboard and bought 4 x 512mb corsair pc2100 ECC ram CM73SD512R-2100/s. i go to build the system and i get no post what so ever. jost long consistant beeps. Referred to the manual and says memory module error. So i think maybe 1 bad stick or ram. so i remove all but 1. same thing. I try every piece or ram separately in each slot and the same thing. The motherboard is new also reset cmos. no change. the board will support pc1600 or pc2100 non-ecc or ecc ram. could be compatibitly issue but leaning towards not atm. so i decide to throw in my corsair value select pc3200 ram into the board and the system posts. i didnt expect ram that is unsupported actually work. I know my luck sometimes is bad with pc's but to get 4 bad sticks or ram. Is it possible i got 4 bad sticks or is the motherboard having issues. like not auto adjusting the voltages for the ram? greatly appreciate your opinions.