ECS 755 A2 memory issue

I am running the above MB with a Sempron 3000+ Skt 754 64-bit CPU and have updated the BIOS to ver 1.1b.

When I try to install a PC2700 DIMM in each slot, the system will not POST and I receive an intermittent tone from the PC Speaker.

When I try a single DIMM then either module will work in either socket so both modules and both sockets appear to be working BUT, they will only show the memory of either module as 256MB when they are both 512MB. I have checked with CPU-Z and this also shows that the modules are 256MB but if I put them in another board then they are correctly displayed as 512MB.

I've never come across anything like this before and any help would be greatly appreciated.

 

It appears that it was the RAM. Whilst I used this RAM previously in another machine without any problems, it seems it wasn't up to the job here. I tried three different versions of the BIOS but it still wouldn't register the memory correctly.

Both were identical Micron Technology sticks according to CPU-Z but they are about a year or so old.

I swapped a single 1Gb module of PC2700 (which is only about a month old) out of another PC into this one and it was working fine. Everything (POST, Windows, CPU-Z etc) reported 1GB present.

Both the old and new RAM look to have fairly similar specs except the old RAM reports a module size of 256MB and the new RAM reports 4MB.

I had 1GB of PC2700 in either machine anyway so it hasn't really made any difference.