I have two HS21 blades for an ibm bladecenter, and I'm having memory problems since I installed 4 DIMMs of 4GB. I suspect the problem is that I bought DDR2 800 instead of DDR2 667, has anyone had problems with this? Is there any way to fix this short of buying new memory?
Check the CAS (Column Address Strobe) timing of the modules. Often faster DIMMs have longer CAS timings. If this is the case then the memory is probably not compatible with your server. Ebay is your friend.