Nat,
No doubt future VP versions will better leverage GPU capabilities to enhance performance. That 3.x is more full featured than the 2.x series may account for some speed differences.
NCH doesn't list system specifics, beyond basic O/S requirements. (At least I haven't found them.) They should. Documentation, overall, is weak.
Here are the minimum specs for another somewhat more sophisticated editor. That said, these requirements seem reasonable in general for the file types listed...
Operating System
Microsoft Windows XP Home Edition, Professional (32 bit with Service Pack 3)
Microsoft Windows Vista Home Basic, Home Premium, Business, Ultimate (32 bit and 64 bit)
Microsoft Windows 7 Home Basic, Home Premium, Professional, Ultimate (32 bit and 64 bit)
Microsoft Windows 8 (32 bit and 64 bit)
Screen Resolution
1024 x 768, 16-bit color or above.
CPU Processor
AVI Capture/Produce: Profiles: Pentium 4 3.0 Ghz or AMD Athlon 64 X2.
DVD Quality (MPEG-2) Profiles: Pentium 4 3.0 Ghz or AMD Athlon 64 X2.
High Quality MPEG-4 and Streaming WMV, QuickTime) Profiles: Pentium 4 3.0 Ghz or AMD Athlon 64 X2.
Full-HD quality H.264 and MPEG2 Profiles: Intel Corei5/7 or AMD Phenom II X4.
AVCHD* and BD* burning Profiles: Pentium Core 2 Duo E6400, or AMD Phenom II X2.
2K/4K/3D* video editing profile: Intel Corei7 or AMD Phenom II X4 with 64 bit OS 6 GB RAM.
Graphics Card
128 MB VGA VRAM or higher (1 GB or higher VRAM and OpenCL capable are recommended).
Memory
512 MB required.
3 GB DDR2 or above recommended for 32 bit OS.
6 GB DDR2 or above recommended for 64 bit OS.
Hard Disk Space
10 GB (20 GB recommended) for DVD production.
60 GB (100 GB recommended) for Blu-ray Disc/AVCHD production*.