I can confirm this as well (64-bit, Core i7, single-disk).

The issue seems to be gone in 3.0.0.

After a few hours working 3.0.0 slows down on me too. The performance
becomes unusable and a reboot is a must. Certain applications
(particularly evolution ad firefox) are next to permanently greyed out.

I have had a couple of corrupted tree logs recently and had to use
btrfs-zero-log (mentioned in an earlier thread). Otherwise returning to
2.6.38 is the workaround.

~mck

-- 
"A mind that has been stretched will never return to it's original
dimension." Albert Einstein 
| www.semb.wever.org | www.sesat.no 
| http://tech.finn.no | http://xss-http-filter.sf.net