IE7 is a great update to old 6.x, but screen drawing is very slow.
I have installed beta3 in three different machines, my testing computer (3.4ghz/2Gb Intel), a second one (3.4/2Gb) and my laptop (2.2G/1G) and page vertical scrolling is much slower than 6.0 on all of them. Even text-only webpages scroll very slowly when using
I thought that something might be wrong with installation so I've installed XP from scratch, updated with all hotfixes and IE7b3. Same results...
Finally I've tried with extoff, although I don't have any third party extensions installed, and with Cleartype disabled but no help. BTW I had exactly the same experience with all IE7 betas and every page I visited, including c9.
Some of my colleagues who tried IE7 betas, had the same slowness issues.