Interestingly, my system specs are lower than Mark (same ram, lesser cpu and videocard) but I get framerates more like spaceace; I wonder why that is?
The most likely cause, off the top of my head, is that Mark, like me, has a dual-core CPU and you have a single-core CPU. That would mean that the demo program can only consume 1/2 of our CPUs (which it does, running at 48%-50% CPU capacity which is equal to 96%-100% of a single core), while it can utilize your entire CPU.
I get a memory access violation when trying to run it directly from the zip file
I also got this. I figured maybe the program was trying to write something back to its zipped location.
SpaceAce