Are the computers the exact same, case and everything? If they aren't that is most likely the reason. If they are the same, it's probably where they are located.
I am literally swapping them in and out of my case benchmarking them etc. Havent put it in my wifes at all.
On a side note i am kinda disappointed in the 1070. I think maybe i am being a little hard to please at the moment. Just fired up a few games at 3440 x 1440 and was met with some pretty tame results. Coming from 1080p and a 970 i was expecting a tad more.
For example. Wow maxed i was lucky to hit 60fps. Even switching to a 1080p monitor same thing. No vsync or foreground limits.
Deus ex MD at 3440x1440 with very high textures and most everything on and no msaa was getting drops to 45fps and 60 most times.
Ran firestrike benchmark a few times between cards and tweaked overclocks that wasn't so bad.
Forza Horizon 3 runs like shit and is all over the place but i think that has some issues at the moment.
I guess was concerns me is that wow should be screaming and it makes me feel i got a dud. Only reason i know i didnt is because i have two to test with. I keep a pretty clean OS and ran DDU to kill drivers.
Oc currentlt at 100+ on core and 400 on memory. Got the non oc strix editions.
Anyways rest of rig is
4670k oc to 4ghz
16gb ddr3 1600
2x ssd and 2x hdd
MSI Z87 G45 Gaming motherboard
Ultra 1000w psu
H100i
H440