GeForce GTX 770 EVGA vs Gigabyte vs Something else

Your English is excellent. I had no idea it wasn't your first language until you wrote that you're from Portugal.

Wow, that's a lot of criteria. Well, the first thing I want to establish is that a GTX 770, I think regardless of manufacturer, will certainly get you 60 fps at 1920x1080 for pretty much any game on ultra settings assuming you turn off SSAA/MSAA for some of the most intensive top tier games such as Metro: Last Light or Crysis 3. However, aside from those 2 games, my GIGABYTE GTX 770 Windforce edition GPU never reaches 99% usage. I personally have issues with my CPU bottlenecking me, but that's just because of my CPU. When it comes to GPU intensive situations, the GTX 770 certainly keeps up.

However, if you're planning on doing a multi-monitor setup, the GTX 770 won't cut it if all monitors are going to be 1920x1080. It only has 2 GB of Video memory, and for multimonitor you'll notice a serious performance decrease in games. If you're going to use the extra 2 monitors to multitask, but only play games on 1 monitor, the GTX 770 will handle that just fine. If you're really serious about playing on 3 monitors at a resolution of 5760x1080 though, both EVGA and GIGABYTE make 4 GB models of the GTX 770 which are both about $450 compared to the standard 2 GB which is only $400. The 4 GB models WON'T guarantee 60 fps on ultra settings, because 5760x1080 is hugely hard to handle even for a GTX Titan. However, the 4 GB vs 2 GB will certainly help. Either way though, if you want bearable frames you'll really want to look above the GTX 770 (or just not play a triple monitor setup).

As for which manufacturer is better, I'd say GIGABYTE. Yes, I am a little biased, but to be fair the GIGABYTE edition has a higher base and boost clock than EVGA. However, realistically they perform about the same. Maybe around 1-3 fps difference in games from benchmarks I've looked at, but that's about it.

Other GPUs include the Radeon HD 7970 which can be anywhere from $60 less to $40 more depending on where you look, but either way there's not much of a difference between it and the GTX 770. I recommend going with the 770 if you want to enable PhysX in games and maintain good frames.

Make sure you get a good PSU (I have 650 W, Bronze rated and it's never failed me) and make sure you don't bottleneck your GPU with a bad CPU. I have an AMD FX-6300 and honestly the bottlenecking really kills me when it occurs. I recommend an Intel i5-3570k or an i5-4670k to pair with your GTX 770. It'll do wonders! A good Motherboard with that is a Gigabyte Z87. It'll work very well and have plenty of ports. Good luck!