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Topic: problem with second R9 280x added to working mining PC in cgminer (Read 2352 times)

newbie
Activity: 2
Merit: 0
best site I've found with a full explanation of all those 7950 mystery command lines and how they work  http://www.bitcointrading.com/forum/bitcoin-miners/cgminer-cpugpu-miner/msg761/#msg761

fixed all my set up issues.
hero member
Activity: 574
Merit: 500
Working ok ,thanks

It's normal to share what your solution was.
hero member
Activity: 613
Merit: 551
Working ok ,thanks
hero member
Activity: 613
Merit: 551
similar problem, any help

Running one r9 280x ok about 750 speed, i install second r9 280x, one run in 750 but second imposible more than 67.

i run with cgminer 3.7.2 and catalyst driver 13.10, i update catalyst to 13.12, i tried cgminer 3.7.0 and 3.5, and i tried many configs but always the same
im using windows 8.1
Im not using crossfire, and not active in software.

newbie
Activity: 17
Merit: 0
The solution (of sorts): once I switched from Xubuntu to BAMT there was no longer any problem. The reason for this totally eludes me, but I am somewhat of a Linux noob and getting a miner up and running was taxing my abilities by itself.
legendary
Activity: 1022
Merit: 1001
Check your PCI-I slot settings in the BIOS
newbie
Activity: 6
Merit: 0
I am also have the same problem trying to run 2 r9 280x.
i have 6 gigs of ram. i was lead to beleive that i would only need 4 gigs of ram to run up to 6 cards. is this not true? if so how mucg ram should i have?
newbie
Activity: 17
Merit: 0
8GB ram seems to be sufficient for this task. I'll do as you suggest and we'll see what happens. Thanks for the thinking everyone.
DrG
legendary
Activity: 2086
Merit: 1035
Don't do crossfire.

Do you have enough system RAM?  If you don't CGMiner will crash and disable the device.

Make individual batch files for each card and launch separately.   Pain in the butt but easier to control for debugging.
jr. member
Activity: 43
Merit: 10
x-fire is no longer needed, cards run perfect without it and as fast (or faster)
newbie
Activity: 17
Merit: 0
You sure about crossfire? I heard that would make hashrate suffer. However, if both GPU's start working to near capacity that's better than nothing I guess.
legendary
Activity: 1554
Merit: 1002
stick them in crossfire. also your gpu temp should be way above room temp. might have a faulty card
newbie
Activity: 17
Merit: 0
750w. But this is not the problem. I had a spare PSU activated and connected to just the second card. No difference.
sr. member
Activity: 259
Merit: 250
What is your power supply wattage?
newbie
Activity: 17
Merit: 0
I have set up a mining computer that functions well with one GPU. However, when I add a second GPU, the machine crashes. When going down to basic settings, cgminer recognizes both cards and seemingly starts mining, but total hashrate is the same as the hashrate for one card. Moreover, shutting down either card does not have any effect at all. The temperature of GPU1 stays close to room temperature as well. Does anyone have an idea what can be wrong?

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