A few weeks ago I built a new PC- it all spiraled out of control from one event. First, my buddy sold me his Nvidia GeForce GTX 480 for $100 (which is a great deal for a fine card). Once I got it home and installed it though, I found that the power supply in my stock 2006 PC wasn't big enough to run it. Luckily, I still had my tax return money sitting around, so I decided it was finally time to get into PC gaming. I went with the Intel Core i7 2600k, 16GB 1600 GHz RAM, a 180GB intel SSD, 800W power supply, blu-ray writer- you know, the works. This things a beast, and so far, I've got no regrets. However, today I bought Witcher 2... it's amazing! Holy fuck, I love it. Here's the thing, I can run it at on my big TV at 1080p at 50-60fps on high. However... on ultra, it only runs at about 20-30 fps (not enough!). I'm pretty sure the thing holding this PC back is the GPU- it's a great card, it's only like one... and a half generations old. I've spent a good chunk of change on this PC- i've got no problem spending a little bit more. Here's the thing though, I've never used multiple GPUs before. What kind of bump would I get from buying another 480? They're going for around $200-$250 right now, and if it's going to be a significant improvement, I'd much rather do that than spend $600 on a 680, and discarding this 480. Also, would my power supply explode? I know I could google all this, but I wanted your guys input. If one of you with expirence can tell me how this SLI thing works, how much of an improvement to gaming it is, basically anything I need to know before making another investment, I'd really appreciate it. Thanks.

I'm not quite sure about how much improvement you'll get exactly, I imagine it would be very noticeable especially for current gen games. But I share your concern about the power supply, 800w seems a bit low for another 480 on top of an already beefy machine.

I've recently built a similar machine. I'd say forget about crossfiring two 480's and spend a little extra money so you can pick up an AMD 7970, or GTX 680. Every component you have is on the cutting edge; it would be a shame to have an older GPU holding you back, even if it is two crossfired ones. On my 7970, I get a solid 25-37 FPS with the Witcher 2 on Ultra settings 1080P with Ubersampling on. Without Ubersampling it shoots up to 70 - 80, or 60 with Vsync. Here is a benchmark test for the Witcher along with some other games.

EDIT: Also your power supply is a hefty bugger. Should easily be able to handle dual 480's or single 680/7970. Minimum requirements for 680/7970 are 550 and 500 watt power supplies respectively.

@rebgav said:

@TooWalrus said:

on ultra, it only runs at about 20-30 fps (not enough!).

Is that with ubersampling on?

Yeah... I suppose I didn't read the fine print there- "only for absolutely top-end systems". Ha, I think I'm gonna try Ultra settings with that disabled. What the hell is "Ubersampling" anyway?

@TooWalrus said:

@rebgav said:

@TooWalrus said:

on ultra, it only runs at about 20-30 fps (not enough!).

Is that with ubersampling on?

Yeah... I suppose I didn't read the fine print there- "only for absolutely top-end systems". Ha, I think I'm gonna try Ultra settings with that disabled. What the hell is "Ubersampling" anyway?

It renders the frame four separate times, and offsets each rendered frame by one pixel. It's basically an insanely nice looking anti-aliasing technique. It almost completely gets rid of jaggies and makes the game look like a "CG movie" as my friend liked to describe it. It's better then MSAA, FXAA and most other anti aliasing techniques in my opinion, including SSAA. However since it's rendering four 1080P images at once, your system takes a heavy beating.

I would save up for a 680, GPU performance isn't all about the numbers (VRAM, clock speed ect). The newer cards should have better firmware/shaders which should help you get better performance. I think that 1x 680 would run the Witcher 2 better than 2x 480s.

@LiquidPrince: Thanks for the advice, Prince. I disabled Ubersampling, and that kicked the framerate to around 45-55 on Ultra, which is fine for now- the game still looks incredible compared to it's console counterpart. I think I'll stick with things the way they are for right now, and pick up a new single GPU down the road. Probably around Christmas, I get a bonus every year that should cover it. Thanks to @EnchantedEcho and @rebgav, too.

@TooWalrus: No worries. Glad to be of service. Only advice I have left is to make sure you run Witcher 2 in no less then 1080P if you can. I was running everything on Ultra at 720P on my old system and it didn't look that great for some reason. I mean, it did look very nice, but not as nice as it should. Later when I got my new PC and ran it in 1080P it looked night and day. I researched why there was such a big difference and basically found out that the Witcher team painted all the textures at insanely high resolutions since it was originally a PC only release. Normally game textures are painted for 720P, but I believe every texture for Witcher was painted at 1680x1050. So if you run it at lower resolutions it actually crushes texture detail making the game look grimy.

Anyways, sorry for the long rant. It was just breathtaking the first time I ran it in 1080P.

If you can afford it, GTX680 or a GTX670, after using dual ATI 5870s i just cannot reccomend an ATI card again after their shocking driver support for the past 3 years with almost everyone i know who owns an ATI has such a incredibly hard time with their drivers regardless of their price-performance ratio. Otherwise the Nvidia 5 series cards have completely plumited since the 6 series came out, you can easeirly find a good quality graphics card and very good prices, hell even dual 560s would absolutely rock everything on the market right now (got a machine that has 2 in sli mode) and that'll only cost you about $400 for two of them. I wouldn't personally get another 480 are the prices on newegg, its getting old, and very overpriced because they've stopped producing that card when you can better it. Best advice i could give is have a look at benchmarks online for the sli GTX 480s and compare them to more current cards, i dont know what the performance would be like for two of them.