VIPRE may show up lighter on the Task Manager, but it slows down the system more than Nod32. Especially when accessing files in Windows Explorer. I tried VIPRE on several systems and it always slows them down more than what Nod32 does. VIPRE also has update problems since it has such large signature files, sometimes updates time out and don't install.
It experienced this problem on several systems, they went up to 3 days with no updates. I had the same problems with Sunbelt CounterSpy back when I used to use it. Never had a problem with Nod32 updating.
Sometimes info in the task manager doesn't show accurate results of how a program will run on systems. The only way to know is to try both and see the different when using your system. Some programs may use less RAM and CPU cycles and still make your system run slower than another program that uses more RAM and CPU cycles.
Anyway, if it was just the choice of VIPRE and Nod32, I would choose Nod32 because Eset have been in the malware business much longer than Sunbelt (now GFI) and they have more experience.
Nod32 might not be at the top of AV testing sites but at least they participate in testing, it is unknown where VIPRE would place in testing.
Thanks.