Memory Woes

I’ve installed one PC100 64 meg memory stick then replaced it with one PC100 256 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 of56 meg, when I install (one)256 meg stick I get a reading of 130 meg in Windows98se(System properties) and the cmos. Using this same memory I get the same readings on two MB both about 2 years old and both support PC100. No error messages.

Here are the specs:
MB: PC100 Systemboard M741 & ASUS P3B-F
Proc: Pen II 400 mhz, System Bus 100Mhz
Memory: pc100 SDRAM (64 meg or 256 meg)

Why won’t my systems give the correct reading with the new memory? 🙁