the thing is, Windows 7 still works slower than XP, slower than Win98, and much slower than WinNT4.0
What we tested so far, Win7beta works fine on a 1,66Ghz processor pc with 2GB of DDR2 400Mhz RAM, and a notebook 5200rpm hd.
It fits also on a 6GB HD.
But this is only the initial installation.
After that many programs will need to be installed that will affect performance, like compression program, anti virus/firewall, perhaps an internet explorer/firefox/.., an office packet, some games, manufacturer specific drivers to 'improve' hardware performance (sometimes to the cost of OS response time), software around hardware like eg: recording or TV software for a TV card, a blueray/DVD playback software, with additional codecs,
recovery software, bloatware standard from the notebook's manufacturer, flash,Java and popup blocker, etc...
Perhaps even some work related softwares like autocad, CAD-CAM, SAP, a warehouse stock program, or other...
How will Windows 7 perform in these conditions?
I know that XP works blazing fast, almost as fast as Win98 or NT out of the box. But that generally is over before even the first service pack is released.
I think even the netbook versions of Windows 7 will be a heavy load for them, if not run from a reasonable fast SSD (at least faster than a HD)!