Hmm I've been having problems with too-slow rendering times w/V7 too. And like V6, it will occasionally have a memory lock-up and the pc reboots, losing all my render progress midway through.
(someone should benchmark render times from V4-5-6-7)
A quick tip:
Sometimes I'll split my render into several parts, rendering each bit, say 1/3 of the
project, out into separate uncompressed avis, then combine those rendered avis
into one big one as a last step on the timeline. Kind of a hassle, but it works since I have each segment rendered out individually.
ken