My Hardware reserved RAM allocation is 2MB in Windows 7 and 770MB in Windows 8 on the same PC. I wonder why.

Windows 8 must have some significant memory management changes in it, I'd assume. Also does your PC have both integrated graphics and a dedicated card? I'm thinking that that could cause something like that if switching the OS caused it to switch back to the integrated and use your RAM as VRAM.

I think it looks like they are trying to compartmentalize the windows processes a bit more, and have the necessary system processes run in an untouchable RAM partition. That would make sense, considering what they want to do with UEFI boot.

I have an ATI Radeon HD 2400 Pro graphics card with it's own RAM. So it could not come from there.

Originally Posted by whs

I have an ATI Radeon HD 2400 Pro graphics card with it's own RAM. So it could not come from there.

That makes me all the more convinced that Microsoft are trying to reduce system RAM usage by having fixed process speeds (at least for the system processes).
Did you run both examinations at idle, with only Windows processes running?

Did you run both examinations at idle, with only Windows processes running?

Yeah, only the snipping tool was active.

Originally Posted by whs

Yeah, only the snipping tool was active.

It's weird then that 8 was using more. I'd've expected it to use less.
Edit: Are you using W8 32bit? Says you've only got 3.3GB available to W8.

Yes, W8 32bit. But you got a point here. It may be using the address space for the GPU, etc.

Ah, okay, that explains the skewed graph then. It appeared as though 8 was using more, when in fact it's using almost half as much.
Do you think you'd be able to get another shot with the 64 bit version? I wonder if there'd be a significant difference.