On a 4 x 1060 rig I use 1.1GB of RAM. On a 6 x 1060 rig I use 1.3GB of RAM. Unless there are spikes of memory usage or a memory leak somewhere, I don't see why 4GB would be more than enough. It certainly shouldn't have any effect on Genoil stability. Genoil seems to give comparable/better hash rates even with lower clocks and power limits than Claymore requires. I've found that dropping the clocks has definitely increased stability without reducing hash rate.
I have two 1070s, and since switching from Claymore to Genoil a few days ago, I've had two or three instances where the rig has crashed on me. My overclock settings had been -200 for GPU and +1200 for memory, which had been stable with Claymore. I've dropped the memory overclock back to +1000; hopefully the crashes will stop.
Even with the reduced setting, though, I'm still seeing an extra 2-3 MH/s with Genoil that Claymore wasn't delivering...and that's before you factor in the lack of a fee for the miner.
