tri-gpu setup

[james49]

as of now iam running 2 sapphire 4870s in cxfire, i want to accurie a 4870 x2. will i be able to run this setup in crossfire, one single 4870 bridged to the 4870x2, and what sort of preformance increase will i see over the cxfire im now running? or mabey wiser to wait for the 4890x2, any thoughts?

[Kenshai]

Well really performance gains from 2-3 gpu's is less than 1-2 but there's usually a pretty big bottleneck via your cpu. Which CPU and clock are you using?

[Tatty_One]

Originally Posted by james49

as of now iam running 2 sapphire 4870s in cxfire, i want to accurie a 4870 x2. will i be able to run this setup in crossfire, one single 4870 bridged to the 4870x2, and what sort of preformance increase will i see over the cxfire im now running? or mabey wiser to wait for the 4890x2, any thoughts?

Yes you can run a x2 with a single 4870 and you will obviously see a performance increase but the more GPU's you have, the less well the scaling so at a guess you might only actually get about 50-60% of the single 4870's performance if that makes sense.

You have not included your specs so I will mention the other factors you need to consider:

The lower res you game at, the less benefit you will see

You need a fast powerful CPU running at about 3.8gig+ to see the most benefit out of a 3 GPU setup, you will of course see benefits still but bottlenecking will further chip away at the performance benefits

You need to consider your PSU..... does it have enough juice for a 3 GPU system.

[james49]

iam running a 750 watt green power psu, phenom 940, 4gb of ram, and windows vista 32 bit. sata 500 gb hd. i have not yet got an after market cooler for the 940 as i cant make up my mind. (any suggustions) also i have recentley put in the asus m4a79 deluxe, and am still learning it.also the 2 4870s work well in cxfire, but the amd overdrive iam kinda leary of using it as im told that you really need to oc from the bios, but i have used it and had the cpu up to 3.2 ghz, but i was worried about heat and stopped, how far will it go with an aftermarket cooler like zalman? then i can run the tri-setup.

[Tatty_One]

Originally Posted by james49

iam running a 750 watt green power psu, phenom 940, 4gb of ram, and windows vista 32 bit. sata 500 gb hd. i have not yet got an after market cooler for the 940 as i cant make up my mind. (any suggustions) also i have recentley put in the asus m4a79 deluxe, and am still learning it.also the 2 4870s work well in cxfire, but the amd overdrive iam kinda leary of using it as im told that you really need to oc from the bios, but i have used it and had the cpu up to 3.2 ghz, but i was worried about heat and stopped, how far will it go with an aftermarket cooler like zalman? then i can run the tri-setup.

Wow, a few questions there, you been on the caffeine? The 750W would probably not be enough for an overclocked quad core and 3 HD4870's effectively so you would need to upgrade therefore additional costs...... where do you live?..... just looked, Alaska! Probably dont need aftermarket cooling up there..... just open the window!

With a decent board and good air cooling you should be able to hit 3.8gig on the 940, people do more but I am taking into account that you dont appear to be an experienced overclocker? Yes, Overclock from your motherboards BIOS always, it's easy, got to the Phenom II thread in these forums, that will tell you all you need to know and you can get some good cooling advice also.