Is the t-rex miner still developing?

I have 4 Nvidia A-4000s, when I try to run all 4 of them, after a while (it can be 5 minutes, 15 or 20) the computer just reboots. With 3 pieces it also reboots. With 2 pieces it works fine. Mining ravencoin. T-Rex 0.26.8, Win 10 Pro