CPU-Z showing up all of my ram but bios/windows is not.

[ebisu]

Hi, i bought new RAM memories (DDR2) for my old computer. I had 4gb (2x2) and now i bought 8gb (2x4) and if i put them both in MB (msi g41m4 (ms-7592)) my computer starts, but i have black screen. If I put there one old and one new computer stars but just with that old one even if CPU-Z is loading both of them and i dont know where is the problem. I'm not computer mage so i manage to get some tips here.
I have 64-Bit system with Intel Core 2 quad q9500, MSI GTX 750ti
https://ctrlv.cz/0mRN -As you can see CPU-Z is showing that i have 6gb of ram but windows is showing just 2gb
https://ctrlv.cz/mcJs - New ram in CPU-Z

 

[julienruc]

What is the brand and model of the new RAM sticks you bought?

This is usually a compatibility issue. You will either need to upgrade your BIOS or you've unfortunately bought the wrong RAM. If it's the later, you should check the motherboard specs online as well as check their QVL list.

 

[RememberThe5th]

The common issue is , double sided ram vs single sided ram double sided is more compatible, usually chip size for instance 64mb vs 128mb, 128mb/256\512 per chip can cause issues like that.
32 bit or 64bit?
Always try to buy ram from QVL list, there is noted ss, ds.