Also will it be enough if I want to SLI later on?
You really like to waste money... But yes, that's over kill for now and just perfect for when you add a second card.
like everyone else said.
i personally wouldn't go with the r9 290x variant of that card though.
the regular non-x version performs pretty close and you can OC it to r9 290x standards.
and the non-x is around 439.99 on Newegg unless the sale ended.
just a tip if you wanna save some $$$
It's a bit overkill for now but if you plan to crossfire you should be good however I have to disagree with MacerV because it won't give you much headroom to OC at all because you do have to have about a 100-200W headroom with Crossfire to ensure that everything is stable and will have enough power at full load.
Here is another power supply calculation website. I've switched from the eXtreme one to this one as it seems to have a bit more detail.
Inputting your part list into the calculator it recommends a 643 watt power supply.
When i add in a second Radeon290x for crossfire to the calculation, it recommends 932 watts. So yes, it is extreme overkill for your current setup but it exactly what you need if you do plan on adding another card for crossfire.
Thanks everybody for the replies, and the reason I went with the more expensive vapor-x is because I'm terrified of overheating with the card, since I've heard AMD cards tend to run a bit hot. Would you guys recommend getting a 780Ti for a little more?
No. The 290x is on par with it, so the extra cost is wasted money. That said, the overheating you heard about was for the refereucards when they first came out, and that was largely due to the early drivers. The aftermarket versions like this one are far superior in cooling and the drivers are far more refined now. This is one of the coolest card series out in the high end markets now.
Few things worth mentioning:
The 290x like others have been saying isn't particularly worth it over a 290 as the performance difference is very small for the extra 100 ish you pay for it. What's more, while the Vapor-X is a great cooler, it isn't worth the money. A lot of people will disagree with me on this but let me explain:
Yes the Vapor-X is very cool, but it doesn't exactly destroy the competition. The powercolor PCS+ is over 120 bucks cheaper than the Vapor-X and trades blows with it in terms of cooling performance and noise levels. As for overclockability, the reality of the situation is the 290/290x gpu die is very oc limited. If you take a look at every benchmark done of them by reviewers to see the overclockability they all hit just about the same levels unless they get a dud gpu die (around 1200mhz). One of the biggest components of the Vapor X that adds to its' cost is the custom PCB it has and the vrm power phases. The reality is these don't really help with your ability to overclock because the power delivery isn't the problem on this platform, the inherent limitation of the GPU die itself is.
Besides that some things worth considering for your build:
The motherboard is ridiculously overpriced for what you're getting. No, it won't help you overclock further, neither will it help you "future proof" your build. You can get a motherboard that provides the same featureset for at least 50 bucks less with the same color scheme.
The 750D is a pretty huge case. Full towers really are better suited for 3+ GPU setups and custom liquid cooling loops. Consider checking out a 450D instead to save money while still keeping the same design aesthetic.
The RM psu you've selected is over priced. You can pick up an EVGA Supernova G2 for 30 bucks less.
Corsair's SP fans aren't really that great. With the savings from the other suggestions you could put the money towards better fans. You could take a look at the Aerocool DS Dead Silence fans or Noiseblocker eLoops for starters.
As for the wattage, if you plan to get a second GPU down the line, it makes sense, otherwise you would be fine with a 750W
Thanks everybody for the help, I agree that a full tower case may be a little over the top for a single GPU, I may look into the 450D as you mentioned.