TYAN THUNDER i7500 S2720 needs RAM

[WizBandit]

I used the CORSAIR memory page but my TYAN Dual XEON motherboard is not listed. There is a close match (S2720-533) but that's not my board and having bought over $800 worth of Corsair DDR memory over the past few weeks that does not work I need help. I have a pile on the shelf now and decided I need to stop guessing and ask someone. My manual says I need DDR PC1600 or PC2100 modules, ECC and registered. they need to be installed in pairs. If I use PC2100 is says it will only run at PC1600 but you can use the PC2100 module if it's more available. The last memory I bought was CM72SD1024RLP-3200/S. The vendor said it should work like the CM72SD1024RLP-2100/S but I can't get the system to acknowledge it. can anyone tell me why the CM72SD1024RLP-3200/S won't work in place of the CM72SD1024RLP-2100/S ?? Is there anything i can do to the CM72SD1024RLP-3200/S to make it work? trace cut? disable SPD? solder some jumpers in? I'm going to loose it if I go ahead and buy the CM72SD1024RLP-2100/S and it does not work. The motherboard boots and runs fine on a pair of CMX512-3200LL DDR modules but they are a bit pricey and I don't need their low latencey numbers. They cost twice what the CM72SD512RLP-3200/S modules do.