Juast as an "FYI:"
Premiere will use multiple procesors, but many/most/all of the plug-in CODECs for it will not. The included CODECs do not, as well as third party plug-ins, for example: Ligos LSX LE or Standard, the INDEO CODECs, Digigami LE or standard, Panasonic, Quicktime, HUFYUV, and the DiVx 4.x and 5.x...
Many of the companies have stand-alone products that DO work multi-processor (Ligos) or CODECs that work in a multiprocessor environment with other applications (HuffYUV, DiVx, MainConcept with VirtualDUb, Flask, or XMpeg), and work well.
To get multiprocessor encoding, using a frame server plug-in feeding a standalone application like VirtualDub or TmpGenc works really well. Basically a frame server plug-in exports the Timeline from Premiere to a filename, and the filename is used as the input to the other application in real-time.
AVIsynth is a fairly popular frame server, I think you can get it at vcdhelp.com, maybe doom9.com (and other places).
RAM is probably more important than processor for Premiere (though a fast procesor is always a good thing). When you start Premiere, it will grab half of all available RAM. If you don't have enough RAM for the length of video you're editing, it may hang or run *very* slow.
If you couple up Premiere with a capture/rendering board, like a Maxtor 2500, DVRaptor, or Pinnacle DV500+ or Pro One, it rocks right along...but you still need absolutely no less than 512M. It'll work with less, but it is still pretty slow. If you use a rendering board (as listed), they have hardware CODECs and will get by with way less processor and still give pretty good render times.
Also, a warning: I have had the Pinnacle DV500+ and the Pro One (still have the Pro One), it is very particular about the system hardware. It doesn't work with most motherboards or video cards. Pinnacle's tech support is slow to respond, and relies strictly on "cookie cutter" answers, they're favorite being "Your motherboard doesn't have enough {PCI bandwidth | Ram Bandwidth | IDE bandwidth - pick one}."
I was unfortunate enough to have selected non-mainstream hadware (as far as Pinnacle is concerned). I have a dual 2.0 Gig Xeon on an Intel 860 chipset with a Gig of high-end RAMBUS RAM, and an ATI DV8500 (retail) video card. I'm using an Adaptec 39160 SCSI controller with a 36G Seagate 15KRPM system drive and a Seagate U160 72G 10KRPM storage drive. This system was running XPPro (supported, according to the Pinnacle website) I tried several other video cards (Matrox 450, GF3Ti500, GF2mx200). The board never worked, the system hung, Premiere failed, captures were grossly flawed....totall unusable.
Maybe I should have bought better hardware.
The DV500+ also failed in a Dual PIII 1G on a VIA 266 chipset, a gig of RAM, and two Special Edition WD 120G harddrives, and an ATI AIW Radeon (and finally the GF3Ti500). Same thing, system hangs, corrupted files, bad captures. This system is running WIN2KPro. This system is operating at a marginal level, captures are OK, but attempting to playback the timeline causes the system to hang. Every Time.
The moral of the story, I guess, is that if you want to run a higher-end Pinnacle board, build the system around it. Due to it's (IMHO) bad hardware interface, poor firmware, and worst-in-the-industry drivers coupled with some of the poorest tech support I've ever had to use, I can't say I'd recommend it.
The Pro One will be going back this weekend.
BTW: The Matrox 2500 worked without a hitch on the original box (2.0Gig Xeon) and the dual PIII. I haven't tried the DV Raptor yet, but I expect to pick one up next month.
Edit: I forgot to mention that I'm using SuperMicro motherboards in both machines (a P4DC4+ and P370DDE).
Sorry to rant & ramble. Hopefully there's some useful information in there somewhere.
FWIW
Scott