Incorrect Ram Reading

In relation to the Post ( Verifying DMI Pool Data message when booting) I did a Memory test with Crucial and it reported 1056MB I have 3 slots and 512 MB in each slot total of 1536 MB Windows tells me that on boot up and both Everest and SIW report 3x512.
Crucial reported only 32 MB in slot 3. I always thought the Crucial Scan was quite reliable.
In frequently asked question it also says yes to mixing PC 2700 (I use) with PC 3200 because they are backward compatible, I would be worried to to that.

 

Just in case anyone would like to know, I have done a Windows Memory test and a Mem Test and both have given me a clean bill of health for my Ram.
I think that the Crucial test was out.
I hope that I can mention this on this Thread without starting a new one as It refers to the same sort of situation.
I was asked to look at a relative's PC that is running very slow, Pentium 4 3.4 (I think) MHz 2 processors when I looked in dxdiag it told me 512 mb of Ram
but both Everest and siw could only see 256 mb. I did not have time to open the case to actually have a look yet.
Normally if dxdiag finds 512 mb everest will do the same could there be faulty Ram aboard.