4 GPUs on riser, one card running much hotter than the rest

[Kaninm]

Last week I finished building my mining rig and have been tinkering around with it trying to get it running the way I'd like.

My setup consists of:
Sempron 140 AM3
Asus mobo
Coolermaster 1000w PSU
XFX 7870(FX-787A-CNFC) x4

Here's a pic of where/what it's sitting in

https://i.imgur.com/yMuQLbb.jpg

I've been having a temperature problem with the second card from the right. It consistently has run 10c hotter than the others. I've tried cutting out parts of the crate in the back to help airflow, installed a case fan directly in front of it, have the card at a lower intensity setting than the others, and have undervolted all the cards (from 1.21 to 1.110 which did help a lot, but only to bring the card to normal operating temperature).

Here's what everything runs at:

https://i.imgur.com/78QxMj8.jpg

Im just trying to find a way to run this rig without crazy temperatures or fans at 100% all the time. Im currently using BAMT so if I'm going to undervolt anymore it has to be through a bios flash, and the next lowest option I have is 0.9, which I think is too low to be stable. Only other option I can see is to have them run in windows where I have better control over the voltage.

Does anybody have any other suggestions? I'm sure there are plenty of people here more skilled at this stuff than me so I'd like to get some input.

[tygarbyte]

I see, 2nd card from right has slight less airflow.
swap 2nd on right with first on left and see what temps you get.

[Kaninm]

I see, 2nd card from right has slight less airflow.
swap 2nd on right with first on left and see what temps you get.

Thanks for the reply!
I did try this already, thinking I might have a faulty card but any card in that spot runs hotter. Im thinking it must be something to do with airflow as well, but I've cur out the plastic piece blocking the back and that hasnt helped any. Either has adding a 140mm fan in the front. The only thing I can think of is heat from the motherboard components making air temperature around the card hotter than the rest?

[Dimrain13]

Well look how the card is put in... you are blocking the air flow on the back side of the card.... either cut out a hole or deal with the temps.