How can 1GB RAM Read as 512MB

Hello

I am having problem with my RAM
You see I bought a 1GB DDR2 667 to replace my 512 MB DDR2 667 memory module. I installed it and booted the PC.

But when I checked the amount of RAM it reads as 512 MB. I have taken the memory module back to where I bought it and got it tested. On their computers it was read as 1 GB. So the module is not at fault.

So I went home and decided to use both modules. The orginal 512MB and the 1GB. When I booted the PC and checked the ram it was 1024 MB or 1GB. Which is wrong coz its suppose to be 1536MB or 1.5 GB.

The only logical reason I can think of is maybe my mobo's max RAM is 1 GB. Which I don't believe coz my manual says the max is 2GB. And there are 2 sockets.

You mentioned that you replaced it with another 667 MHZ RAM. But then your you said that your manual says that your motherboard supports a maximum of 2GB.

I think you either didn't press and insert your RAM evenly so that all in flat in the connector itself and that the notches are connected and keeping the RAM down evenly. Maybe your motherboard does support 2GB RAM. But maybe thats with the latest BIOS revision updated that is also reason for facing this problem, So go to your motherboard vendor and look for the latest NON-BETA updates and update that system board.

Are you purchase 1 1024MB RAM or 2 512MB RAM ?

Are you seeing that in BIOS or from Windows ? How much memory is detected in BIOS ?

Thanks friends

Maximillian, Right now I'm using 1 512MB and 1 1024 MB. But the OS reads as 1024 MB.

The 1536 MB DDR2 SDRAM I read from a diagnostic tool PC Wizard 2007. By right clicking the My Computer properties it says 1.00 GB RAM.
I wasn't really able to see how the BIOS reads the memory coz it was in K and very fast.

Press the Del key repeatedly while booting (or F2 or F8 on some mobos) to enter BIOS and see the amount of System Memory detected. Generally it is shown in the first main screen towards the bottom.

As per my knowledge 2 memory slots motherboards don't support irregular RAM memory sizes. It might be because you got a 512 then a 1GB. Try and make it either 2 512 or 2 1GB. And see if this solves the problem. Another solution might be RAM incorrection.

When I turned on my PC and checked the RAM it said 512MB. When yesterday it said 1 GB. Both modules are inserted and I didn't remove any.

Used PC Wizard again and it said A1 was empty. That's where the 1GB was placed. But I was pretty sure I had inserted the modules correctly. So I restarted. And then this time it reads as 1GB.

Thanks for help