50% RAM detected/used

[Bizwithabullet]

Hi Guys
My computer only registers/uses 50% of the available RAM. I have tried switching the memory cards and replacing with other memory and I get the same results. 512 shows up as 256 and 1024 shows up as 512. My local "technical expert" has told me to just add more RAM 2gb so I'll have 1gb usable. I was wondering if anyone had any ideas to fix this besides replacing the motherboard
Cheers Steve

Hi
Only 50% of my RAM is detectable/usable. I have tried swapping around and changing with other memory cards. The result is always the same, only 50% of the installed RAM works. 512 equals 256 1024 equals 512. Any ideas other than changing motherboard?

[Kylebrn]

What is the configuration of your pc ?? Whether both the ram are of same mhz ??? while installing ram, always insert larger stick(s) of memory in the first slot (slot 0) and the smaller one should be in the second slot (slot 1). Try doing this. Then go to bios and find "reset NVRAM" and select "yes".

[Bizwithabullet]

Yeah both memory are same speed 400mhz. The problem is that even if only one memory card is installed it still only registers 50% of its value. 512 equals 256. If the memory wasn't working at all I could simply replace it but there must be something else not working or not switched on. Any more ideas?

[SecRecy]

Make sure that you have gone through the following threads because you can find some solution here:

• New RAM not detected in HCL desktop PC.
• Doubling the RAM

[Bizwithabullet]

Thanks guys. Unfortunately those links didn't help. I have a sis755 motherboard and I'm using 2 x DDR 512 400mhz. The system is five years old but was running fine until last week when my Hard drive started giving me problems. I local PC repair guy installed a new 40gb hard drive and windows media addition OS. He left the old Hard drive (200gb) as a slave so I can have the extra memory and access to most of my old files. When he was working on the system he told me I only had 500mb and should up grade. When I opened the case I found 1024 (the original memory still in place). I have since tried swapping round and changing the memory with spare cards. The result is always the same 50% detected on each card. Any other ideas. Perhaps I should just buy 2gb and live with 1 gb usage.