4GB DDR3 only 1.99GB

I've just upgraded my computer from a DDR2 2x2GB+ASUS M2N32+AMD 5200+ to 2x2GB DDR3(!)+ ASUS P7P55D PRO+Core i5 750. It's the same Win7 x64 ultimate on both configs, but now at system info it says: 4,00GB RAM (1,99 usable). What is with the other 2?? In my old PC it had access to the full 4GB. The modules are brand new and working, I checked them with memtest86, only the windows can't use them. Please help!!!!

Are the ram sticks of the same brand, are their bios timings correctly configured ?

What is the total ram shown in windows task manager > performance tab ?

Is any system RAM dedicated to other tasks by the BIOS (BIOS cache, graphics, etc.)?

You may need to upgrade bios and/or reinstall windows.

In task manager there is only 2 GB, the RAMs are identical (dual kit), and bios is on default except for boot priority. I've just reinstalled windows, so I don't think it'll help. And BIOS must be the newest version, cause P55 boards just came out 1-2 months ago.


Extraordinary Member
Have you tried swapping banks around and testing each stick?


Fantastic Member
Microsoft MVP
I agree with Highwayman - try swapping the modules around. What does CPUz say? Note that many new graphics cards "share" memory. I suspect that is where yours went.

I experienced the same problem after an upgrade from 2 GB (2x1 GB) to 4 GB (4x1 GB). Only 1.99 GB usable.
I solved it by removing the mobo battery for 2-3 minutes. After reinserting the cell and restarting, everything was OK. All 4GB seen by Windows and the experience index went from 5.5 to 7.5.
Hope it will work for you too.

another idea - clean the ram contacts and make sure sticks are seated properly - sometimes it needs a little push to make it snap in

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