Wow, those specs should have handled SampleTank 3. I was going to ask if you have an SSD, but you answered that. Did you have trouble running it in Standalone? What DAW did you use? Those specs should be able to run SampleTank4. More RAM is always better but 8 is the recommended.

Sqk
_________________________
GEAR: Yamaha MOXF-6, Casio MZX-500, Roland Juno-Di, M-Audio Venom, Roland RS-70, Yamaha PSR S700, M-Audio Axiom Pro-61 (Midi Controller). SOFTWARE: Mixcraft-7, PowerTracks Pro Audio 2013, Beat Thang Virtual, Dimension Le.