Which TriFire card to run the monitors on an ASUS Maximus IV Extreme Z

Hi guys,
Bought a ASUS Maximus IV Extreme Z and have installed 3x 7970's in it. The problem, is this:

I note from the manual, If I am reading it right, that the top slot will revert to 8x with Intel chipset, and the bottom two will run at 16x on the nvidea chip.

So, if thats true, my question is:
Should the monitors be plugged into the bottom card or the top card?

At the moment, they are in the top card, and thats teh one that gets by far the hottest, but my thoughts are:

1) Its the slowest transfer rate yet presumably doing most work to run the cards?
2) Its the hottest position, above 2x 7970's with limited airflow. (Very limited... see images)





Any advice will be greatfully received.

My understanding from a tomshardware article about dual cards running in 8x vs 16x was the performance loss was negligable, but I do not know how that effects tri-card setups. I would assume that plugging into the 16x cards would be best, but you should wait to hear more from more experienced people. You could always run some benches both ways and see if there is much if any difference at all.

I doubt you'd see any real difference.. Connect your monitors to any. Doesn't really matter.. Probably the first card in the line though is usually the best bet. 8x 8x 8x vs 16x 16x 16x.. Barely any difference really.. + Your board is Gen 3 right? PCIE 3.0? Whereby an 8x slot is effectively a 16x slot from PCIE Gen 2.0? (Though.. I think this only applies when Ivy Bridge comes along.. I think Sandy Bridge is limited to PCIE Gen 2.0)

Either way; the performance hit; if any, will be within a few percent.. Maybe 2-3 percent at max?

What case is that?