Crossfire with different cards

[krackajak]

Hi guys,
Other than trying to get my post count up, had a few crossfire questions.

Currently I have a 5850 (2 crossfire connections) as a central card with one 5830 one either side, each one using one of the 5850 connections. This give me tri crossfire which can be seen on my windows machine with phoenix. However, trying to overclock with trixx only shows one set of settings.

Is the 5850 downclocking to jive with the other two cards?

Does the 5850 take the overhead hit for running the crossfire?

Should I run linux instead so I don't have to use crossfire? (I was told linux could address all three cards individually with no crossfire bridges. )

Thanks,
Jeff

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[cryptomint]

If it's a dedicated mining rig try LinuxCoin (http://forum.bitcoin.org/?topic=7374.0). I've been using it for a while and haven't had any problems.

You should be able to use 4 GPUs in windows. You can use 8 in linux.

I'm running 3 cards without crossfire in a windows 7 x64 rig (2x5850+1x5830).

Have you tried running without crossfire?

[Deaddy]

Just out of curiosity: Is there any significant speed boost with crossfire, except for a little less CPU-Load? I mean, you can as well run one miner per device.

[krackajak]

hmmm.

Well, I know when I turn crossfire off in the driver, windows still sees 3 separate cards. But unless the crossfire is enabled, the miner has problems picking them up via device number. I am using phoenix 1.50

[7iain7]

you don't need to use crossfire in fact you will get better results not using crossfire at all.
for windows to see all the card that are not connected to a monitor use this work round: http://www.xtremesystems.org/forums/showthread.php?200444-DVI-to-VGA-Dummy.....56K!