512 mb VRAM shown as 1024 mb VRAM in Windows 7

I have a 512 mb 8500 gt ddr2.
When i check my approximate Total memory in xp using dxdiag command under display tab, it shows a normal 512 mb graphic memory.
But windows 7, it shows 1023 mb as total approx memory and memory shared with system as 511 mb.
What does tthis mean???

That’s an error by Win 7. The memory of a slot in graphics card should never be seen as shared memory.

Shared memory is for the situation with on board graphic solutions. Those graphic adapters will use (share) part of the motherboard RAM.

Do you have the latest Nvidia driver?

If thats the case… my graphics cards have 4GB of memory total. ;D ;D

I have latest one-195.62.

I never read of this error in reviews.

That’s normal.
That’s not a bug or error.

Windows 7’s Graphics memory architecture is different from Windows XP.

Please read following docs.

Windows 7

Windows XP

It’s little bit hard to understand how to calculate the size of memory for you.
So I’ll give you the formula.(you can find in the docs)

Total Available For Graphics memory= (Total System Memory - 512) / 2)-1
What is ‘1’? it’s for BIOS allocation.

Dedicated Video Memory: it’s on your real VGA card.

Shared System Memory = Total Available For Graphics memory - Dedicated Video Memory

Total system memory = RAM???
I have 1.5 gb ram.
The formula you have given is for calculating total approx. grahic memory. Not shared graphic memory??