i switched to an hd camera (vixia hf 10) and now everything played back in the preview window is so slow and choppy that the edits are undistinguishable. is this a sign that i need more ram?
No, you need a new computer (and enough RAM too, although that will come together with the new PC). AVCHD is much more demanding in CPU power than HDV or DV cameras. According to your profile you only have 512 MBs of RAM, and yes, this is not enough for HD editing. You need 2-3 GBs to do HD editing. However, EVEN if you had 3 GBs of RAM, it would still not be enough to edit HD, because your CPU is old.
The free way of going around the problem, is to use proxies, but the workflow is convoluted (mostly because the freeware AVCHD decoders are all based on ffmpeg, which is buggy with AVCHD). I can help you out with that, and give you instructions, but I warn you, it's a pain in the rear if you want to do it right (and losslessly).
Honestly, if I were in your position, I'd buy a new PC. Life's too short to waste it on transcodings and convoluted workflows. Either that, or sell that camera and get your old one back.
mmm, yeah, i was almost afraid to ask because of that answer but hey (along that same line of reasoning) life is too short to go back to hi-8: ) so anyways, what else would the ideal candidate computer boast in the way of specs and/ or brand?
and speaking of brand, should i expect the canon camera to get along nicely w/ the sony software otherwise?
Any modern PC with 3 GB of RAM will do. I configured such a machine the other day at DELL for less than $600. Also, DELL had a very nice 23" 1920x1080 LCD for $160, which is dirt cheap, and very useful to edit your footage in 1:1 size. Keep your old monitor to hold the Vegas interface, and use such a monitor to preview full screen at 1:1 size!
Yes, other than that, Vegas will be ok with AVCHD. However, if you want to shoot in PF24, which is one of the modes on the Canon HD cameras, then you must purchase Cineform, in order to remove pulldown before you edit. Vegas can't remove pulldown by itself for PF24 footage.
I'd suggest you wait and upgrade to whatever new is coming in the future. Keep 8 for now, upgrade later. AVCHD support was re-written for Platinum 9 you see, so your version will be barely usable.
I have a good computer with 8GB of ram and it still happens. I would say not to worry because when you render it (if you do it rihgt) it will come out perfect