Can a 550w XFX Core Edition power xfire 7850?

think it can just went onto extreme power supply, but has anyone done this on a 550w psu before?

you do meet the minimum requirements of 500w.

Per XFX "Minimum of a 500 Watt power supply." is required.

AMD say this to cover themselves, the 7850 only uses around 150 watts on full load I believe, but am wondering if anyone has got Xfire 7850 in a 550w PSU.

Check the amperage on the 12 volt rail

If you have a single rail with more than about 38 amps it should be possible

If you have2 12 volt rails of 18 amps each one of them running the two graphics cards is going to get hot quite quickly

Try it and see . If the PSU is any good when it gets hot it may just shut down , rather than catch fire and burn your house down

it does have 1 rail, i knew this when I got it, hense the reason I spent the extra £15 on a decent brand.

and it has 44 amps/ 528 watts just on that rail

Most manufacturers would call that PSU a 650 watt

It would probably be OK, under full load you should be looking at something like 400-450W. I wouldn't do any crazy overclocking or add loads of hard drives though.

short answer:

YES!

the XFX 550 core edition is an outstanding PSU.

more than enough ,,

The stated tdp for a hd7850 is 140w, but it normally only uses about 110w when gaming(if you don't overclock). If you do overclock(highly recommended to get the most from a 28nm gpu) you won't exceed 150w per card(unless you do some hardware modding, which is not recommended). Your i5 3570k is a 77w cpu(more like 100-125w if you overclock which is recommended to get the most bang for your buck out of that unlocked cpu). These parts will pull the vast majority of +12v power from your system(compared to other parts). Even when overclocked, those parts won't pull anywhere near those wattages during normal use(ie gaming). Only if you did something like run prime95 and furmark at the same time would you be close to max draw, and even then you wouldn't be close to those adjusted tdp numbers. The xfx 550w(built by seasonic) can supply more than its rated wattage(if pushed to extremes). Even with capacitor aging, your xfx 550w should power your i5 3570k(overclocked) and 2 hd7850s(overclocked) without issuefor years. 2 hd7850s are similar in power draw and performance(both stock and overclocked) to a hd7970(stock and overclocked). I've recommended xfx 550w for configs with a hd7970 and a more power hungry phenom II x4 965BE(overclocked to 4ghz+). As long as you aren't using a ton of HDDs or optical drives, you'll be fine.