GTA 5 fps drop in sli 760

[Rimex]

Hi, i have issue running gta 5 my fps drop from 60 to 20 and below when i turning mouse very quickly. And i dont know where is a problem. I think it can be ram issue because it using nearly all rams from 7.88 usable. Or it can be sli. Thx for your time. My rig Asus z97-a. i7 4790k stock. Hyperx beast 2x4gb 1600mhz. 2x Gigabyte gtx760 windforce x3 2gb. Psu evga 850g2

 

[Rimex]

On single card fps ~35 stable on same settings. Ram ussing 7.3gb