2nd GPU Hashrate Low - EVGA OC, Claymore, or Something Else?

Hi all,

I am running the following setup:

Asrock 970 Extreme3 Motherboard
EVGA 1060 GTX in PCI-E x16 Slot (x16 Mode)
EVGA 1060 GTX in PCI-E x16 Slot (x4 Mode)
Claymore Dual Miner

Using EVGA OC, I have the Power set to 50% and Memory overclock at +750 which yields 22-22.5 Mh/s for ETH (and a fan speed around 20%/temp of 64-67c).

On the second card in the x4 slot, it has the same EVGA settings but is only giving 15 Mh/s.

If I don't use the EVGA OC, Claymore reports them both at 19 MHz/s in their stock form.

What I am wondering is why when using EVGA OC with the same settings for both cards, why the 2nd one is over 7 Mh/s slower.

Could this be a Claynore issue? I thought about the MB Bios, but when I leave them both in stock form, they are equal... which makes me wonder if it's something weird with EVGA OC.

Any ideas of how to fix this so that Claymore sees them as running equal at 22 MH/s (which is what GPU 1 does using the same EVGA OC settings as GPU2)?

Thanks!

ZZB