I have committed to a 3-monitor setup and am looking for guidance on video card configuration.
I currently have a GeForce GTX 260 driving two 21.4" LCD's, and the performance in the game I'm currently digging (Rise of Flight) is acceptable even at 3360x1050 (full native res). Not to say the performance couldn't be better, but I can live with it..
I've just purchased my 3rd identical LCD, and need a 2nd video card to drive one or two of the screens. My questions are:
1) Generally speaking, am I asking for configuration and driver issues going down this path in the first place?
the main driver issues are with technologie that used 2 gfx cards to drive one large screen (crossfire etc), much less so with driving one screen per card, or 2 screens per card, but this can varry from game to game
2) Should I consider one mid-range card to drive one screen, and keep driving two screens with my 260?
3) Should I instead splurge on a 285 and drive two screens with that, saving the 260 for just one?
largely will depend on how demanding the specific game is on pc grunt, RoF is a good example where you need a high end gfx card and good modern cpu/mb/ram system to play it on reasonable settings so it looks good on a SINGLE screen. so you will need a high end gfx card to drive 2 screens, and a higher-midrange card to drive the single screen. trying to skimp on the gfx card will mean you have to cut down detail settings. the fact you dont use 1920 x 1200 on your screens is a good help, and the lower resolution in the smaller widescreen monitors you use will make things much easier
4) How close do the cards have to be in order to not have color differences across the screens? Is same manufacturer a safe-enough bet?
usually the main issue is that the screens, and panel technology used, needs to be the same or very similar, or you will get significant differences in colour tones and clarity etc.. most gfx cards from nvidea and ati nowadays are very generic in design and many manufactures make the exact same cards with a few cosmetic changes. if you can, it would probably be safer to stick to same manufacturer and series cards, but that is more to do with driver compatibility.
5) What else am I not considering?
being able to use 3 monitors in a game will greatly vary from game to game, it is not just simply a matter of having a pc that is powerful enough, so ask questions in the game forums that you intend to use it for. for ex, in RoF there are some issues right now for a 3 monitor setup, and the bugs are being worked on by the game creators (at least that is what they say). il2 has had an annoying bug in one of the 3 screens which has never been fixed also (flashing black square)
most people that use 3 screens use the matrox 3HTgo unit (digital would be best), and on their website you will see a list of supported games