Oh, how do see the timings inthe BIOS? The voltage for the RAM was actually 1.8 from bios, when my xms2 needs 2.1 V.
OK, set it to 2.1 and pray. That might be it. Timings are in different placses on different BIOS - usually under 'chipset options' - but there is a good chance the BIOS detected those correctly so just try the voltage thing and see.