New rig (2x 5870) crossfire question/problem

[kstepyra]

Hi,

It's my first topic in here, so don't yell at me if i post it in wrong place:)

I am going to buy new computer for pc games, but i am also going to use it as rig. It's going to be 2x 5870 GPU's.
The question is - if i have windows 7 professional 32bit (can change it to 64 if needed) i will be able to run miners on both gpus? or i will have to change anything/install software or something?
Also i heard about turning out crossfire. How does it affect mining / games? or it's impossible to mine on crossfire?
A nice explanation on topic will be nice as i've seen on wiki that there are 5870 x 2 statistics.

Best regards,
Jakub

[c-rock]

I am running a Win7pro 64bit with two 5870s. 

I had no probs running miners on both gpus.  You have to have two miners running.  Change the Device to =1 and =2 for each miner bat file.

I did not crossfire them.  It does not matter for the 5870s.   You can have them crossfired, or not.  Same performance either way.

Make sure you upgrade your PSU.   I would recommend a 900Watt or higher PSU.



c-rock

[kstepyra]

Nice, ill give it a try in couple days. Btw - you are mining with normal GUIMiner? And what's yours mhash/s ? i heard it can go up to 400 and over it with little OC and specific card parameters

[c-rock]

Using poclbm and was getting 358 on my first card,
and 370s on the second.


I could push them more, but they would crash. 
You need to just work it up to a level that is borderline crazy.   

[Meni Rosenfeld]

Make sure you upgrade your PSU.   I would recommend a 900Watt or higher PSU.

You don't need a 900W PSU. You need a high-quality PSU such as Seasonic X-series, 750W tops but 650W should do fine too. Anything which is not from a known brand is utter junk, and even within a brand some products are good and others not so much.

[benjamindees]

It's amazing to me how awful the PSU market has become.  I had good luck with Antecs for several years, but I have one here (SP-450) that crapped out, because apparently it had defective capacitors.  "Japanese capacitors" is now a feature that is used as a selling point.  Wattage ratings are completely useless.  Oh well, I'll try my luck with Corsair.

[c-rock]

Make sure you upgrade your PSU.   I would recommend a 900Watt or higher PSU.

You don't need a 900W PSU. You need a high-quality PSU such as Seasonic X-series, 750W tops but 650W should do fine too. Anything which is not from a known brand is utter junk, and even within a brand some products are good and others not so much.

you might be able to go with a smaller one, but your efficency will be lower, plus overclocking does use the juice more.   I still stand by my recommendation.    A bigger PSU will have better effiencies. 

[Meni Rosenfeld]

Make sure you upgrade your PSU.   I would recommend a 900Watt or higher PSU.

You don't need a 900W PSU. You need a high-quality PSU such as Seasonic X-series, 750W tops but 650W should do fine too. Anything which is not from a known brand is utter junk, and even within a brand some products are good and others not so much.

you might be able to go with a smaller one, but your efficency will be lower, plus overclocking does use the juice more.   I still stand by my recommendation.    A bigger PSU will have better effiencies. 

For efficiency the most important thing is to get an 80+ Gold one. Once you do that increasing the power rating will have almost no effect.