memory limitations and ATI hypermemory

[Marin85]

Hi,
since ATI FireGL 52xx uses Hypermemory technology, I was wondering if it is -at least theoretically - possible that the fourth GB of RAM in a T60p gets utilized by the GPU. Depending on OS/drivers hypermemory can be up to +256 MB (XP) or up to +768 MB (Vista), which is in fact a plenty of physical memory. Actually it would be very nice, if the GPU doesn´t interfere with the physical memory utilized by OS. Since I have really no idea on what basics the hypermemory technology works, any insights, thoughts, comments or ideas are welcome!

Marin

[aaa]

IIRC it was a chipset limitation, regardless of GPU.

[erik]

the 3GB to 4GB memory space cannot be addressed by anything because that address range is taken up by other devices.   since windows cannot address that range, the last 1GB cannot be used by anything else.   if your GPU utilizes physical system memory on top of its own then it will use memory addressable in the 0GB to 3GB range.

only systems supporting memory hoisting can address that last 1GB because the BIOS moves the address range above the 4GB mark.   the only 32-bit OS to support memory hoisting is windows server 2003.   the only chipsets supporting memory hoisting are the intel GM965 and PM965 as found in the X61 and T61 series.

unfortunately that last 1GB is totally useless in a T60/p except to put your memory in dual-channel mode if using two matched modules.