Need help with PSU's :D

[Hyponyx]

hey guys i know a fair bit about components but i know absolutely nothing about PSU's thus the reason for creating this thread. Anyways i am currently part way through a mid to high build and i have had to rethink about a PSU because the Radeon hd 7970 requires 650w minimum, So i need some recommendations on some power supply's that are 50 pounds and below and 650w+.

Oh and if someone could actually explain what makes a good psu that would help me

 

[clutchc]

Here's one of the best sites when it comes to reviewing PSUs: http://www.jonnyguru.com/modules.php?name=NDReviews&op=Review_Cat&recatnum=13
Look for A quality manufacturer like Corsair, Seasonic, XFX, Antec, to name a few. Here is a list compiled by xtremesystems.org a few years ago:
http://www.eggxpert.com/forums/thread/323050.aspx

Besides simply looking for the total wattage, you need to pay special attention to the +12V rail(s). That is the circuit that does most of the heavy work in the PC. The gfx card, the processor, drives, fans all run off the +12V rail(s).

The HD 7970 is a 250W card when maxed out (before O/C'ing): http://www.hwcompare.com/11275/radeon-hd-7970/
That will draw almost 21 amps on the +12V rail(s). (250÷12) And of course, you'll need to have 2 x 6 pin aux PCIe connectors.

But I doubt you'll find it easy to locate a 650W+ quality PSU for under 50 pounds.

 

[Dark Lord of Tech]

A Radeon HD 7970 - needs at least 30A on the 12v rail and a at least a 500W power supply with one 6 pin and one 8 pin power connections.

This unit is 550w and 44 amps on the 12 rail , made by the best SEASONIC.

PCPartPicker part list / Price breakdown by merchant / Benchmarks

Power Supply: XFX 550W 80+ Bronze Certified ATX Power Supply ($49.99 @ NCIX US)
Total: $49.99
(Prices include shipping, taxes, and discounts when available.)
(Generated by PCPartPicker 2014-01-06 18:27 EST-0500)

 

[sora]

A Radeon HD 7970 - needs at least 30A on the 12v rail and a at least a 500W power supply with one 6 pin and one 8 pin power connections.

This unit is 550w and 44 amps on the 12 rail , made by the best SEASONIC.

PCPartPicker part list / Price breakdown by merchant / Benchmarks

Power Supply: XFX 550W 80+ Bronze Certified ATX Power Supply ($49.99 @ NCIX US)
Total: $49.99
(Prices include shipping, taxes, and discounts when available.)
(Generated by PCPartPicker 2014-01-06 18:27 EST-0500)

This, get a SeaSonic/XFX 550W PSU and you're golden