I'm building my first PC and I plan to use a Radeon HD 6790. The problem is all the different manufacturers. I do not know which one is the best. From what I see, it looks like XFX is the way to go, but I'm not sure. Have you bought one before? If yes, what brand?
Which brands are you considering ? XfX is working fine for me but there are many other brands and really all of them seem to be reputable. even some brands they are not selling in the north american market are still good.
Also consider the various cooling systems and warranties available. In the end it's all the same card, with different bonuses. For example, MSI and HIs are good in the cooling departmen while XFX has the lifetime warranty. It is what it's worth to you.
Just a clue, AMD makes ALL the chips. The more expensive examples usually have better cooling systems that will be quieter under load and afford more headroom when overclocking. Also, some of them have "binned" chips that clock higher and are selected for that reason.
Double D first choice
IceQ x second choice
But it is up to you what you want and not what we want. You have been given a lot of good advice here and you should be good to go with what you want to do. Good Luck to ya