Max usable RAM on win7 64-bit?

[Pyromaniac]

Hi. It just occured to me that all of my RAM sould be usable now that i have upgraded from vista 32-bit to win7 64-bit. As i understand it, the professional edition limits RAM to 192GB, so there shouldn't be a problem. Yet when i look under 'system', the memory line reads;
"Installed memory (RAM): 4.00 GB (2.94 GB usable)"
Why isn't it all usable then? That doesn't make any sense to me? Is that a limitation of my chipset or something?

[123456]

Maybe your BIOS has a 3GB limitation somewhere... turn that off.

[Pyromaniac]

i'll have a look...

[Pyromaniac]

Well i had a poke around my BIOS and it said i had 3008 MB of installed memory, but there was no option to change that or remove any limits.

[PrntRhd]

The hardware (mainboard) may limit the amount of RAM addressed independently of the amount Windows 7 64 bit can address. I think that was what 123456 was saying.

[Pyromaniac]

yeh i guess so. It's not a big problem, i'm getting by fine with 3GB, it just seemed a shame to be wasting that extra GB.

[saphalline]

i have upgraded from vista 32-bit to win7 64-bit.You did do a fresh install, right? Because you cannot perform an in-place upgrade from 32-bit Vista to 64-bit Win7. It needs to be a fresh install.

Also, in the future, I recommend using a Linux live CD to double-check funny hardware reports like this that you see in Windows. If Linux sees 2.94GB, then your BIOS is the issue. If Linux sees all 4GB, then something is not right in Windows.

[123456]

BTW: Home Premium of 7 is limited to only 16GB RAM... while Professional and Ultimate are limited to 192GB

[Pyromaniac]

Yeah, i did a clean install (both HD's completely wiped) of Windows7 Professional. It's funny that windows recognises that i have 4 GB installed but only 2.94 GB usable. Is that the sort of thing you'd expect from BIOS limitations?