I've been given four 1GB Corsair DDR2 memory modules, and am trying to fit them into my computer but am getting BSOD on Windows XP and errors in Memtest86+. I've tried to identify if one particular module is faulty by trying them in pairs. They work fine in pairs, but when all four are inserted, Memtest86+ reports errors. The motherboard is an Asus P5N-E with dual channel support and the modules are all the same model (same speed, capacity and timings) but one pair is a different hardware revision. One is v2.1 and the other is v2.2... the voltages are the same too. Would this minor difference be a possible cause of the problem? I've got the BIOS memory timing settings all at AUTO - should I manually set the timings?