how to crossfire two 3870

knockonwood · 14 Jan 2008 at 19:47

ok a friend of mine has just bought another 3870 and is trying to set them up in crossfire correctly, but seems to be getting mixed results is there various settings that must be set....

thanks :confused:

Gerard · 14 Jan 2008 at 19:48

Make sure cat ai is set to standard for crossfire, also make sure the enable crossfire option is checked in catalyust control centre. Also make sure he's using both crossfire bridges on top of the cards and not just one.

knockonwood · 14 Jan 2008 at 20:09

hi here is his settings at press he says very screwed up results

Gerard · 14 Jan 2008 at 20:25

Looks ok, what kind of weird results is he getting?

knockonwood · 14 Jan 2008 at 20:41

LOL i hate being the middle man

he is losing the plot i think... getting a bit stressed :eek:

the reply i got when asked

They are crap I got better with a single card

is there a program to test the cards ? to see results score?

Gerard · 14 Jan 2008 at 21:01

Not sure what would be wrong, mgith want to run 3dmark to see if both cards are functioning properly.

Jakus · 15 Jan 2008 at 01:54

Gerard said:
Make sure cat ai is set to standard for crossfire, also make sure the enable crossfire option is checked in catalyust control centre. Also make sure he's using both crossfire bridges on top of the cards and not just one.

You do not need 2 bridges, 1 is fine

Gerard · 15 Jan 2008 at 01:55

JAKUS said:
You do not need 2 bridges, 1 is fine

For 3870 you need both bridges, only the lesser cards make use of one bridge. When i had crossfired 2900's performance was wonky with one bridge.

Jakus · 15 Jan 2008 at 02:43

Gerard said:
For 3870 you need both bridges, only the lesser cards make use of one bridge. When i had crossfired 2900's performance was wonky with one bridge.

Take a Guess why only 1 bridge is required !!...O Yes so the other bridge can connect up crossfire X setups..

knockonwood · 16 Jan 2008 at 05:57

ok guys he mailed me the result yesterday after hours of fooling around with it

tbz_ck · 16 Jan 2008 at 09:45

Something in the BIOS perhaps to enable the two gfx cards?

I used to have to do that for SLI on an ASUS A8N-SLI-SE........

knockonwood · 16 Jan 2008 at 09:57

ok i will mention it , he tried joining the forum but his email addys are not allowed.

thats not a bad score though LOL beats my 8800 gts (10289)

Jakus · 16 Jan 2008 at 13:12

Yes It must be the motherboard, Has he tried running just from the lower card/PCI-X slot ?

LoadsaMoney · 16 Jan 2008 at 13:21

Has he got a 4x pin molex from his PSU plugged into the board to supply extra power for Crossfire.

The 4x pin connector is next to the 24x pin, you can see it on this pic at the top.

http://www.tweaktown.com/popImg.php?img=gx38l_8.JPG

jrodga2k5 · 16 Jan 2008 at 13:29

Also he must check the jumper settings on the motherboard for his second PCi-E slot as I had this problem and crossfire would not work until I swapped them to the correct settings for the speed

Scougar · 16 Jan 2008 at 13:32

Install dotnet framework 3.0. and your cards should work

(<< This is pretty much essential and is not included as any part of an ati install at present

)

Matthew

knockonwood · 16 Jan 2008 at 14:24

thanks guys for your support

as soon has he logs online i will send him the link to this updated thread .

im using framework 3.5

but i bet he is using a version less than 3

thanks again i will post the outcome hopefully positive

Scougar · 16 Jan 2008 at 16:51

Not sure what 3.5 brings to the table, but might try it later as it's an incremental upgrade from 3.0 + "dotnet 3.0 SP1" it seems?

Matthew

knockonwood · 16 Jan 2008 at 16:59

Scougar said:
Not sure what 3.5 brings to the table, but might try it later as it's an incremental upgrade from 3.0 + "dotnet 3.0 SP1" it seems?

Matthew

lol im just a sucker for trying new software :eek:

knockonwood · 16 Jan 2008 at 20:30

hey guys here is the mobo he is using http://www.gigabyte.eu/Products/Motherboard/Products_Overview.aspx?ProductID=2665