Yup. AVC editing was just functional in Vegas 8, and for some camera output, not stable. Also, for any serious HD work, you really want the 64-bit version of Vegas. Vegas 8.1 was the first 64-bit release, but it was more of a technology preview… it had issues.
While its true that Canon’s Quicktime format is a bit easier on the CPU than AVCHD from a camcorder (Canon uses I and P frames only, plus 44Mb/s bitrate, rather than IPB frames and 24Mb/s… B frames require more CPU and memory to process), I would still want a fairly modern 4 to 6 core CPU with 8GB memory.
That doesn’t have to be the very top of the line stuff, either. I saw 16GB of RAM on sale at Newegg this week for $60 or so. I have long been an advocate of buying technology “at the knee of the commodity curve”. At commodity prices, when pay twice as much, you get twice as much. At the high end, you might pay twice as much for only 25% more performance, maybe even less.
-Dave