New Gmail is slow

I find the new version of Gmail quite slow and CPU intensive, not only on my ASUS R2H which is somewhat understandable as it's a mere 900 MHz Celeron w/o L2 cache, but even on my work laptop, a 1.8 MHz Dothan CPU. It seems to be worse in Internet Explorer 7 compared to Firefox, the CPU spike stays up for longer.

You can switch to the previous version by clicking the Older Version link in the top-right corner, but that doesn't make it remember next time you open Gmail. So the obvious solution - to some, for me the penny dropped after two days of pain :-) - is to actually bookmark the address to the old UI http://mail.google.com/mail/?ui=1 instead of the usual http://mail.google.com/.