I assume you're a professional Game Designer / Developer / 3d Artist, or somewhere in between.
- As for your current PC selections, its all OK except your video card and psu, WHY?.
Lets focus on your main concerns to see why. Im gonna make it short but informative.
1. First of all, you need a video card that features a full 30-bit display pipeline (for maximized visual fidelity),
and can support synchronization to external sources or synchronization of 3D renders of multiple GPUs and
capable of HDR output and can interact with very huge datasets. Since your current choice (5870 video card)
can only process traditional 24-bit display pipeline (even if you CrossFireX it), which produces only 16.7 million
colors and with few hundreds shader engines in total, that alone is enough reason that wont surely help you a lot
on your real time renders, complex design models and scenes and while animating.
If you spent a whole lot of time working as Game Designer / Developer / 3d Artist, then you'll need all the
rendering and 3d multi tasking power you can get and i recommend (if you're willing to spend a lil more for
a maximized output in return and to do what ever your imagination tells and your demanding client asks you to do),
the ATI Fire Pro 8750 2GB GDDR 5 video card will suit all your demanding needs.
http://www.amd.com/us/products/workstation/graphics/ati...
http://www.tomshardware.com/news/amd-ati-firepro-studio...
This has all the very important features (i said above) and gpu processing power in order to handle very very
complex dynamic multiple 3d renders and animations and will cost you $1,800 dollars but its worth it believe me.
And if you're willing to spend a lil more for the sake of bagging those hefty pricey design contracts
that requires more gpu computing power you can also crossfire two of 8750's but not an 8750 and a 5870
because they have different API's and architecture (not really sure).
2. You need a reliable psu and at the same time runs quietly?
Based from your current specs and even if you decided to buy two Fire Pro 8750's and crossfireX it,
an 850 watt psu is more than enough to handle all your components at its full continuous load all the time 24/7.
I recommend these:
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
If this is not available,
Go for this instead.
http://www.tigerdirect.com/applications/SearchTools/ite...
3. RAM? You'll need 9-12 GB for sure. Corsair Dominator's?..
If this is what you mean:
http://www.tigerdirect.com/applications/SearchTools/ite...
My answer is a big YEAH! What if its not available, any alternative?
This one, a big YEAH too!
http://www.tigerdirect.com/applications/SearchTools/ite...
-- When it comes to gaming, a single Fire Pro 8750 performs the same as 5870 (just not sure exactly in benchies).
In anyway, this means you can play the latest demanding games at very high settings without any glitch.
The only advantage a Fire Pro 8750 has is when it comes to 3d multi apps, multi renders, animations and HDR outputs
coz Fire Pro video cards are mainly designed to handle those specific tasks and not mainly for gaming, though
a part of its use is for game design but, its a different thing im sure you get the point.
-- You mentioned overclocking?.. Well, a fast hot overclocked i7 cpu really needs a good cpu cooler and
i highly recommend this
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
here's why,
http://www.xbitlabs.com/articles/coolers/display/scythe...
Hope this helps