Did you try asking cgminer to control the fans? Such as:
[code]–auto-fan [/code]
Also you can set a temp target in the config, like this:
[code]–temp-target 75[/code]
I found that the hotter my cards get, the more work is rejected (thats with 280x). In other words higher temps and hash rates seemed to be a false economy.
Also, you’re likely to struggle with those cards in a case. It doesn’t sound like you are using any other form of cooling? A slow, but large desk fan makes a massive difference to my rig… just sayin’ ::)
[b]PS.[/b] I limit the intensity to 13 on the newer cards, as recommended by cryptobadger. Wonder if the 290x is a similar case.