Memory Woes

I’ve installed one new PC100-64 meg memory stick then replaced it with one new PC100-256 meg memory sick on my motherboard. I always get the wrong reading in Windows98se(sys Properties)and during bootup in the cmos. When I install (one)64 meg I get a reading of 56 meg, when I install (one)256 meg I get a reading of 130 meg in Windows98se(System properties) and the cmos. No error messages. This occurs on two MB that are about 2 years old.

Here are the specs:
MB: PC100 Sytemboard M741 & ASUSP3B-F
Proc: Pen II 400 mhz, System Bus 100Mhz
Memory: pc100 SDRAM (64 meg or 256 meg)

Why won’t my system give the correct memory reading? 🙁