Hi Ian,
WOW, that's pretty low
It took me forever to get a screen shot because I'm using this funky Audio/Video keyboard where the normal keys are assigned to different functions.
The first screen shot is from my cheap $399.00 E-Machine which has 2GB of RAM, a NVidea 6100 nForce 405 graphics card, AMD (K8 Family) @2.41Ghzprocessor, NVidia nForce Network Adapter 128MB memory, VIA Envy24PT (Multi-channel). All on located on main board, except for the sound card. That window that appears in the screenshot, I could not remove it, but the rating for Calculations was 4.3 and memory was 3.9.
The second screenshot is from Vista, although I had Windows 7 on it for a short period of time. The performance index was the same. It has a Intel(R) Core(TM)2 Quad CPU Q6600 @ 2.40GHz, NVIDIA GeForce 8500 GT 512 MB memory (HDMI), ASUSTeK Computer INC. (Burbank) board, ASUSTeK PureTV, Intel(R) 82566DC-2 Gigabit Network, Sound Blaster X-Fi Xtreme Audio (optical in and out)
All I can say is Microsoft's system requirements only include the necessary hardware components, but if you really want performance, you'll have to update your hardware to a mid or high-end components for true performance.
Just a note, I don't know why the correct picture isn't showing up in my signature.