Windows XP detects only half my RAM

Question from Blue13X
“Hey guys. I have a P4 system with RDRAM.
I had 4 banks with each 64mb, totaling 256.
So I took out 2×64 and in place put in each bank 512.
so now I have:
bank 1: 512mb
bank2: 512mb
bank 3: 64mb
bank 4: 64

But instead of 1152mb it shows only 640.
of the 512 mb sticks of each it only sees the half.

Any idea why and how I can fix this? ”

Answer from Gdusa1
“If your motherboard supports dual channeling then bank 1 and 3 should correspond to each other. Anyways it is not suggested that you use ram of different size, speed or manufacture since they may not be compatible with each other. The additional 128mb is not going to make any significant differnce so I think it is time to part with your 64mb sticks. Do you have a mobo manual? ”

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Answer from Grumpy9117
“No, according to the manual the mobo supports 64 – 512 MB modules. The 512 MB modules should be in Bank 0 with the 64 MB in Bank 1. “

Alan is a web architect, stand-up comedian, and your friendly neighborhood Grammar Nazi. You can stalk him on the Interwebs via Google+, Facebook and follow his ass on Twitter @ocmodshop.