I am planning a new build. The parts I have chosen are listed below:
My question is: is the GPU on that list sufficient for all the components? Also, if it is, is the GPU somewhat overkill? I am asking this because I want to make sure that the GPU I choose is obviously enough, but also not too much as it would waste electricity. I think that 50w over the perceived wattage requirement will be sufficient.
Overkill is relative to the games you play and the resolutions that you game at. The HD 7850 is a great performing GPU, is very power efficient, and will play almost any game at highest graphics settings when gaming at HD resolution (1920x1200). The PSU is more than sufficient. Actually it is sufficient for two HD7850s running in two-way Crossfire mode. The ZS 550W is more than sufficient for a system running a single HD 7850 and will have significant power reserve for extensive OC of the CPU/GPU.
You're welcome! Between those two I would go for the 965BE. I'd actually go for an i3 2120 with a decent mobo over either of those. The HD 7850 has enough power to take advantage of the extra processing power the 2120 brings to the table.
The 7870 is better than the 7850, but it's not an earthshattering difference. The ZS 550W is also sufficient for the 7870 and overclocking. Another PSU recommendation is the XFX Core 550W: http://www.amazon.co.uk/XFX-P1-550S-XXB9-PRO550W-Editio... It has 6A more on the 12V rails, two more years of warranty, costs the same, and is made by Seasonic - arguably the best PSU mfr on the street. Between those two I would definitely go for the XFX Core 550W.
The i3 2120 is only 5 quid more than the 965BE and the 965BE has to be heavily OCed to match the performance of the stock 2120: http://www.scan.co.uk/products/intel-core-i3-2120-s1155... The motherboard prices are probably similar. There is no good upgrade path for the Phenom II mobo (maybe a 980BE)and the Phenoms are starting to be phased out. Getting a Z77 board allows you to go with an Ivy Bridge CPU later on or potentially the successor to the Ivy Bridge. It just makes more sense from a stock performance and upgrade path perspective.