New videocard

[Tigger29]

System Manufacturer: XFX78I
       System Model: XFX nForce 780i 3-Way SLI
               BIOS: Phoenix - AwardBIOS v6.00PG
          Processor: Intel(R) Core(TM)2 Duo CPU     E8500  @ 3.16GHz (2 CPUs), ~3.2GHz
             Memory: 2814MB RAM
          Page File: 1288MB used, 4547MB available
        Windows Dir: C:\Windows
    DirectX Version: DirectX 10
DX Setup Parameters: Not found
     DxDiag Version: 6.00.6001.18000 32bit Unicode

I didn't realize your motherboard supported SLI... you could find another 9800gtx+ and SLI it easy enough, but I think you're going to find that you'll see a MUCH better gains 'for the buck' upgrading to an ATI

[Krusty]

But the 9800 GTX should only be roughly 10% slower than the HD 4870, so you should be pretty OK already.  (edit -> and the GTX+ overclocked should be just about comparable, from what I can see...)

Just going off the specs from the cards, not really benchmarks, the 4870 has far more potential.

It has about 50% more memory bandwidth, performs 3x as man FLOPS, and nearly twice the memory speed. Pixel rate and texture fill are about the same ballpark.
That means doing more, and getting it to and from the memory, faster than the 9800 GTX+.
link: http://www.gpureview.com/show_cards.php?card1=571&card2=564#

Of course, not all specs tell the whole story, but I like to look at them for a comparison of overall capabilities.

We go up to the 5850 (not even the 5870) and we get even faster memory speeds, about 80% more memory bandwidth, almost double the pixel fill rate, and about not quite 20% increase in texture fill rate.
Link: http://www.gpureview.com/show_cards.php?card1=571&card2=614
(you can find them for as low as 289.99 on newegg)

We have a winner! 



EDIT: Or, as mentioned above, go SLI. That depends on your PSU supporting it and being able to find the same card to match with your existing one, since they don't have many 9800 GTX+ being sold anymore.

[jdbecks]

what are the benefits of SLI? Ive never looked into it

[Krusty]

Originally, there were almost no benefits. For a long time SLI took twice the money, twice the power, twice the headaches, and returned a net of only 10% extra performance. Now, it's been around a while and the drivers and technology is a bit better.

Generally speaking, you're getting 2 cards but not twice the GPU power. Two cards, but they both need to process the same things, they still share an I/O and other bottlenecks. One card does odd frames, the other does even, or depending on how they are set up one card does the top half of a screen and the other the bottom.

I would say you probably get (wild guess) 30% boost with SLI. From reputation, crossfire (the ATI version of SLI) seems a bit better, but overall I'd say if you can do it with a single card it's better than running 2 lesser cards. <-- that is purely my opinion, though.

[Spikes]

The most you can get from a Crossfire setup is about 45-50% increase. So I'd venture to say 30-40% increase from SLI.

[gyrene81]

Originally, there were almost no benefits. For a long time SLI took twice the money, twice the power, twice the headaches, and returned a net of only 10% extra performance. Now, it's been around a while and the drivers and technology is a bit better.

Generally speaking, you're getting 2 cards but not twice the GPU power. Two cards, but they both need to process the same things, they still share an I/O and other bottlenecks. One card does odd frames, the other does even, or depending on how they are set up one card does the top half of a screen and the other the bottom.

I would say you probably get (wild guess) 30% boost with SLI. From reputation, crossfire (the ATI version of SLI) seems a bit better, but overall I'd say if you can do it with a single card it's better than running 2 lesser cards. <-- that is purely my opinion, though.

What he said... 

One little thing you need to research though...you have an Nforce 780i mobo...that may cause issues with ATI graphics cards...it's newer than mine so I'm not sure but I can't run ATI on my mobo without major headaches...some sort of compatibility issue with the Nforce chipset.

[jdbecks]

What he said... 

One little thing you need to research though...you have an Nforce 780i mobo...that may cause issues with ATI graphics cards...it's newer than mine so I'm not sure but I can't run ATI on my mobo without major headaches...some sort of compatibility issue with the Nforce chipset.

cheers mate, something I did not know and will think about.

going SLI increase my video memory? I can get another 9800gtx + for £100.

[Spikes]

IIRC the gfx mem is not increased...but don't quote me on that.

[Krusty]

Technically you get 2 cards, 2x the memory...

Realistically, each card is using its own memory, and still doing the same amount of work, so you don't really get extra video memory.