I literally just got the second card yesterday, so I'm brand new to the CFX experience, but I'd like to know which card should be my primary (in the first PCI-E slot). The XFX reference model I have comes with a double lifetime warranty, but the Sapphire second revision has better cooling. I just threw the Sapphire into the second slot because I didn't feel like uninstalling the first one yet, but now I want to ask: should I put it into the primary slot? Again, new to CFX, but it seems that the first card is ALWAYS running, where the second card only kicks in during 3d applications. Right now, I want to leave the XFX card where it is; my justification is that, if it fails, its warranty will let me replace it, and since it is 'always' running while my computer is on, it's more likely to fail (although hopefully NEITHER fails before I'm done with this build!). However, the Sapphire has better cooling, and to me this means that it would make more sense to put it in the primary slot -- constantly running, its non-reference design would likely last longer (in theory) than the XFX.
Am I thinking too much about this? Does anyone else have a similar situation?
EDIT: The Sapphire is this one; as you can see, it ain't reference.
You clearly didn't read the question. Do so again.
Put the one with the better cooling solution in slot 1. It just makes sense. The slot one card has less air flow because of the card right next to it. Once you switch them though, you'll probably have to uninstall and re-install the video drivers. I had the same situation when I had to move my cards around after I bought the second one with a better cooling solution. I know it sounds funny, but every little change like adding a card and swapping slots always required a driver re-install for me with my AMD cards.