I just started mining ETH and I have two GPUs, RX480.
One of them has a low hash rate while the other has a normal has rate.

This is what I am seeing:
GPU #0: Ellesmere, 4096 MB available, 36 compute units
GPU #1: Ellesmere, 4096 MB available, 36 compute units
ETH - Total Speed: 26.880 Mh/s, Total Shares: 15, Rejected: 0, Time: 00:34
ETH: GPU0 4.307 Mh/s, GPU1 22.572 Mh/s
Incorrect ETH shares: none
Pool switches: ETH - 0, DCR - 0
Current ETH share target: 0x0000000112e0be82 (diff: 4000MH), epoch #125
GPU0 t=50C fan=22%, GPU1 t=72C fan=44%

GPU0 t=49C fan=22%, GPU1 t=73C fan=44%
ETH: 05/25/17-17:45:15 - New job from us2.ethermine.org:4444
ETH - Total Speed: 26.879 Mh/s, Total Shares: 15, Rejected: 0, Time: 00:34
ETH: GPU0 4.308 Mh/s, GPU1 22.571 Mh/s

Why is the one so much slower?
I have my monitor plugged into one of them and I am using risers on both of them.
One is plugged into the PCIEx16 slot while the other is plugged into the PCIEx1. Should they both be in a x16 slot?

Thanks for the help

Cancel that!
I swapped to both PCIEx16 slots and now i'm getting 22.6 Mh/s on both cards. I dont know if that did it or restarting did it. I guess I'll find out more when I buy more GPUs