Hi,
the Synths from the V-Collection are a bit different. So you speak of the Synths or Spark? I'm on Windows 7 64bit and use Studio One 2 as a DAW. What I've tested is V-Collection in standalone mode and as a VST in the DAW. My machine has got an Intel i7 4,0 GHz Cpu and 16GB RAM - I experienced no freezes so far.
As I cannot say anything about Mac environment, a few screenshots of the issues would help, also your configuration of the soundcard maybe.
I had an issue with Spark crashing when Kits are loading, now it seems gone, because I did a few things:
1. used another soundcard with their ASIO driver
2. deleted the .prefs files of the Spark Software
3. returned the Spark library to the default folder
The V-Collection was simply installed with the Arturia installer (automatic downloading of the whole collection and install).
Ok, and here two pictures of the Arturia V-Collection (2 Instruments of it) combined with Spark in the Studio One 2 DAW. I have to notice, that 4GB were used by the OS System including Firefox Browser running, plus Virus Scanner.
The CPU usage didn't change and the RAM popped up from 4.5GB to 5.11GB (including the running DAW). So I would say, the resource needed for this is not much (ok, it's not a whole song, but so far it should work without any disturbance).
Like I said, a screenshot of your usage in ProTools would be fine.