Steve Thackery

Andrew,

I'm not sure you're really listening to the previous responders. I'll spell
it out...

32-bit Vista can only address 4G of memory addresses in total.
Memory-mapped I/O must sit inside this 4G address range, Depending on what
you've got by way of hardware, the top half to three quarters of a Gig in
the 4G address range is used by the memory-mapped I/O. The video card is
the biggest user of memory-mapped I/O.

So, even though you have 4G of RAM, the top 0.5 to 0.75 Gig is disabled
because it occupies the same address range as the video card, et al.

There are two ways to get round this:

1/ Install Vista 64 bit. This can address much more than 4G, so the I/O is
moved out of the way of the physical RAM.

2/ Some BIOSs support remapping, which requires a 64-bit processor (which
I'm sure yours will be). I don't know for sure whether it moves the I/O up
above 4G, or some of the physical memory, but basically it allows Vista to
see all 4G of physical memory AND the memory-mapped I/O. Only some
motherboards/BIOSs support this - mine doesn't.

Steve