7850 upgrade

you will most definately need a new PSU to crossfire 7850s. upgrade to something around a 750w or 800w would be necessary (unless you get something uber efficient like an 80+ platinum 650w, but that would be expensive).

may I ask what you need the upgrade for and if you can wait? there will be a new generation of cards coming out later this year Q2 and Q3.

as for an upgrade path, if you can get a decent deal selling your 7850, I would do that. single card solutions are always easier to deal with drivers wise. but either way, you'll need that new PSU, the 7970 is a power hungry card.

im completely rebuilding a system to run eyefinity and the 7850 (from benchmark) struggles doing so.

for eyefinity definately sell your 7850 for a 7970. if anything the extra 1GB of video memory will help too

as for PSU, get something like a 750 or 800w corsair PSU, you should be able to find a reasonably priced one

vmem is right about single cards, though you really won't need that much PSU. The TDP on the 7970 is 250 watts. Factoring in the rest of your system, it's unlikely you'll need more than 500 watts. Can't say for sure though without knowing the rest of your spec. The quality of the PSU is also a consideration - a cheap brand 500w PSU often won't actually deliver 500w without problems.

Oops on my part, my head was completely stuck around CF, and then I said 7970 so I thought "CF 7970??"

you're completely right, 750/800w psu would be overkill for a single 7970. I stand by my recommendation if you want the potential to crossfire with a nother 7970 in the future. otherwise, get a quality 500 or 550w PSU and you'll be good. Thanks samplay

is a TX650 sufficient enough?
Also right now i have fx4100 which i will be upgrading to (hopefully) a 2500k or a 3450

Corsair is a strong choice, as is your CPU. Keep in mind 2500K is for overclocking, 3450 isn't. vmem's comment about a 750 watt PSU to allow a second card in future is a good one, though it means you'd be drawing more power than you need in the meantime.

PSU's don't draw more from the wall than they need (so don't worry - you won't be pulling a constant 750 watts), however they do lose efficiency when they're under-utilised. If total wattage is fairly closely-matched to your actual hardware needs (what's called "full load"), less power is wasted in conversion.

Other side to that argument is that if you do then decide to Crossfire after buying a 500 watt unit and can't sell the 500 when you buy the 750 you need, more money is wasted than the added electricity costs if you just got the 750 in the first place. To be honest, it's not the end of the world either way though - important thing is to have enough power (obviously) and get a quality brand that won't die and/or damage components.

Be aware Corsair and Antec, though frequently recommended, don't actually build PSUs. That doesn't matter (most PSU brands are not manufacturers) as long as they are supplied by OEMs (actual manufacturers) that are quality. Of the OEMs, Seasonic are the widely regarded as the best. Seasonic-built PSUs include all XFX, Silverpower SP-Sxxx / SP-SxxxM / SP-SS lines, PC Power & Cooling Silencer series and Silencer Mk III series. Plus obviously any Seasonic brand model.

EDIT: And that TX650 you mentioned by the way is a CWT-built unit. CWT have been known to manufacturer some quality PSUs, but also some pretty bad ones. Useful resources:

http://www.realhardtechx.com/index_archivos/Page673.htm

http://www.tomshardware.co.uk/power-supply-oem-manufact...

I have seen the antec delta psu's but they are expensive thats why i chose the tx650 unless you can send me any link to good psu's in the UK

Use these:

scan.co.uk
ebuyer.com
dabs.com
novatech.co.uk
aria.co.uk

in conjunction with resources I linked and you should find something good. XFX are a good bet for cheap Seasonic-based units. And Delta have done some REALLY good PSUs, quality OEM.

I see that you are battling between a single 7970 and two 7850s and let me just break it down for you, performance wise two 7850s perform better than a single 7970 usually but in power consumption the 7970 uses less power.

If you already have a 7850 then go with crossfire if not get a 7970 so you can crossfire that in the future, I actually have two 7850s in crossfire and they work quite well I get performance that beats 7970s and 680s.

While you're right, I would argue that the performance difference is small, and could turn the other way since the OP wants to use this set up for eyefinity