I don't understand Sli or Crossfire

SlugForAButt · 25 Sep 2009 at 00:08

Well, like I said. I need to know a few things.
Do you need similar/same type boards?
Do you need special software?
How do you set it up?

Atm I'm running 4870, but I'm guessing the principle is the same for both manufacturers.

Just some plain speaking would be nice please.

Lanz · 25 Sep 2009 at 00:13

google

crossfire wiki

then

sli wiki

antran · 25 Sep 2009 at 00:15

with crossfire you can pair it up with other brands or even a 4850

sli is much more strict, must be the same model/brand

Nocky24 · 25 Sep 2009 at 00:18

Whats your full spec? (Particularly your motherboard)

SlugForAButt · 25 Sep 2009 at 00:19

Yep Lanz, It helps with crossfire a little.
Thanks for nothing really, I'm beholden to you, obviously.

SlugForAButt · 25 Sep 2009 at 00:20

I got a P5Q PRO TURBO with a 4870, can I bang any old 4xxx in with it?

SlugForAButt · 25 Sep 2009 at 00:21

Thx Antran, this is what I needed to know. Not how to Google (thx though EssexBoy).
So with Crossfire I can mix 'n match?

LeJosh · 25 Sep 2009 at 00:22

ASUS P5Q will run Crossfire fine.

Buying another 4870/50 will increase performance.

No special software just the latest CCC and enable "crossfirex" in the CCC's control panel.

Edit - Added note, it has to be the same generation I believe with ATi so any 4xxx series will work. I think.

SlugForAButt · 25 Sep 2009 at 00:24

So will it make much difference sticking a 4850 in with my 4870?
I'm running an o'c 7500 @ 4Ghz, is that going to bottleneck before the Crossfire?

LeJosh · 25 Sep 2009 at 00:25

What's your resolution?

And also the 4850 will sort of hinder the 4870 so probably best getting another 4870 they're pretty cheap now anyways.

CrossFire Chart

Also that CPU shouldn't bottleneck it, depends what game you'll be playing, such as GTAIV, ArmA 2... etc. you'll see slower performance on a Dual core. (Why can't I ever bloody remember all quad core recommended games I don't know)

unknownsock · 25 Sep 2009 at 00:27

If you put a 4850 in with your 4870, the 4870 will run at the same speed at the 4850.

Any combination always runs at the slowest cards speed.
Generally you will need all cards to be similiar model.

SlugForAButt · 25 Sep 2009 at 00:28

Lol, that's a moot point.
I like max res (1080p), but I mostly run at lower res so my wife can play facebook games properly without shouting me to change the res.

SlugForAButt · 25 Sep 2009 at 00:29

Am I right in thinking that the lowest memory is a factor too?

LeJosh · 25 Sep 2009 at 00:31

Do you feel like you need another for more performance?

If you're satisfied with the games performance just now then why bother?

bifday2k · 25 Sep 2009 at 00:34

Id agree with lejosh the 4870's are getting so cheap now, no point looking at the 4850..

SlugForAButt · 25 Sep 2009 at 00:35

I don't feel I need more performance atm.
I also dont need more than a C2D 2.9 atm either but I have it o'c to 4.0Ghz.
But obviously I'd like to know because I don't know atm. That's all.

LeJosh · 25 Sep 2009 at 00:36

Well it's an option for the future if you ever see games starting to get a bit sluggish.

Hope I helped.

SlugForAButt · 25 Sep 2009 at 00:40

Thx chaps, it has been a help (Essex excepted), I get the basics now.

unknownsock · 25 Sep 2009 at 00:41

No if you add another GPU it just improves the bandwidth.

Eg.
You add another 4870 1GB to one already excisting. It will still be 1GB but with the bandwidth of 2GB.

LeJosh · 25 Sep 2009 at 00:49

You're right unknownsock. If the VRAM in a game is 500MB then that data will be on both cards and will cap at 1GB.