New GPU for old i7 dell. 7850?

The hd7850 will not run on that 350 watt psu, especially if you have an i7 along with that. You should upgrade your psu, to say a 500 watt. The hd7850 is a very nice card.

I was under the impression it was very difficult if not impossible to upgrade PSUs on a Dell branded desktop?

What is the form factor of the case? Is it a mid atx tower? What kind of PSU does it have now, the size, is it an atx form factor psu? If it is then you should have no problem upgrading it.

I think the hd7850 would be a perfect fit !!

I too own a Studio XPS and recently started gaming on it. I purchased an HD 6850 on the same PSU and it works like a champ. After much research Dell PSU's are actually UNDER rated.

I have had no problems AT ALL. BUT - once I started ... I just had to build my own. So I did !! It's awesome !! Much better than my old Dell (which is still a solid machine) for gaming.

Good Luck!

Great to hear from someone with a similar situation!

My only concern with the with the 7850 (http://www.scan.co.uk/products/2gb-xfx-radeon-hd-7850-c...) is how it's powered. There's only one 6 pin connector coming out of my PSU. Don't most newer cards require 2 x 6pin?

The hd7850 requires only one 6pin connector actually, so that won't be a problem. However AMD recommends a 500watt power supply.

http://www.amd.com/us/products/desktop/graphics/7000/78...

Great! Thanks.

As for the power draw, there seems to be a lot of people out there saying that it will be fine as GPU manufactures often overstate their power requirements, and PSUs often understanding theirs.

Eg http://www.techpowerup.com/reviews/Axle/GeForce_GT_240/... the 4850 peaks at only 147w.

Surely I should be fine with my 350w rated PSU?

Well you have a dell 350watt, and they are often underrated as someone said before. And yes it is possible to run a hd7850 as it only draws 256watts under load with the system combined, according to:

http://www.guru3d.com/articles_pages/amd_radeon_hd_7850...

It is not guaranteed, but you should be fine as the hd4850 you have draws more power than the hd7850.

One more thing, how much amps (A) do you have on the 12v rail on your power supply?

You would need to upgrade the psu. I recommend this one.
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
And yes the 7850 is a good choice for the gpu. It's plenty powerful as is without overclocking. And with overclocking it can be clocked to performances just under a stock AMD Radeon 7950.

You will not be fine with a 350 watt psu. You need 500+. The card itself takes around 230 watts and your cpu take around 200. Then you must factor in that if you have a low watt psu it puts the gpu on strain, causing it to deteriorate quicker. SO you do need at 500 watt +.

But with today's prices of psu's you could get something nice for about $50. Like that seasonic for $69 Limerick posted.

The card does not take 230 watts. A hd7850 only takes about 100-120watts under load. It cannot take 230 watts, as it has only a pcie connection to the motherboard which provides 75watts, and a 6pin connector which provides 75watts, so a total of up to 150 watts. The cpu is also a factor of course and yes around 200 watts is a good estimate. So his system will be cutting it close, at about 350watts of power under heavy load. However it is said that dell psu's are underrated, so he should be ok, but there is not guarantee. However i do agree that it would be worth investing in a nice 500 watt psu.

My bad. I was thinking of my 7950 when I was writing that.  

With regards to powering the 7850, is one 6 pin connector enough? As far as I can see that's all I have coming out of the PSU.

This review states that 2x6pin are needed http://www.guru3d.com/articles_pages/msi_radeon_hd_7870...

No.

You WILL need to upgrade the PSU.

Why not get a quality 500watt psu for about $50? It would guarantee that your gpu would work, better for the long run.

I've had as many people tell me it's fine as it as (as the previous card drew more power than the 7850 will), that I have had of people claiming it would never work.

I'm having trouble deciding which side is correct

your old 4850 used about 120 at most while the new 7850 will use 130 at most so I say it will run as long as you have enough amps on the 12v line

I will say that it should work, although it would be better to get a new PSU. However the hd7850 will not use more than 120-130watts so you should be fine.
I did a calculation, and assuming you have a i7-920 (draws quite a bit of power), and some other basic components, with a hd7850 your system would draw between 310-330watts. So as long you have about 28Amps on your 12v rail you should be fine.

Hope that clarifies it a bit

By the way, i used this calculator:
http://www.extreme.outervision.com/PSUEngine

You can try it your self too.

Since the 350w has a 6 pin 4850 that worked, and the 7850 is a single 6 pin card as well, I think you should be fine.

Dell also rates their PSU lower than its true capabilities.