I use 3 Vga
GPU0 4GB Sapphire R9 290x
GPU2 2GB Asus R9 270
GPU2 4GB MSI RX 480 X Gaming
First run (no mod) GPU2 : 24Mh+ : Core clock 1275, Mem Clock 2000
Second run (modded) GPU2 : 30Mh : Same clocks, so: 1175, 2080

Greetings!
Is your card Hynix of Samsung or some other memory.
Unfortunately I have hynix. (Just bought those 6 cards) with 1500 strap I cant use anything more than 1950/1000 for memory. Any help will be great. Cheers