i have one R9 290 with no changes i made by my own, mining at 0,83MH/s direct coming from the dealer, and drawing 370W on air. May be a standard 290 is less...i like to compare with my other 290

gigabyte 970A ?

i only see 2 PCI-e slots. Did you find aother board with same name? For 2 GPU fine with me....

may be took the wron topic, but i did some tests on it:

https://bitcointalk.org/index.php?action=profile;u=189723;sa=showPosts

how do you do cooling? airflow? i assume its not a good idea to use a 1000W power supply. Propose a 1200W.

Greetings

had some investigation on watercooling on R290 cards with full waterblock in comparision of airflow cooling. Like to exchange on power consumption reductions on Linux, any proposals are wellcome.
Found powersavings just occure on low temperature. This means up to 40W for a single R9 290.

Test 2
• 730W power supply
• 1x R290 Saphire watercooled @44°C 0,76MH/s
• 1x R290 Gigabyte aircooled @85°C, fan @65% 0,82MH/s
Result-> 686W

Test 3
• 730W power supply
• 1x R290 Saphire watercooled @51°C 0,76MH/s
• 1x R290 Gigabyte watercooled @53°C 0,82MH/s
Result-> 648W

Test 4
• 730W power supply
• 1x R290 Saphire watercooled @42°C 0,76MH/s
• 1x R290 Gigabyte watercooled @43°C 0,82MH/s
Result-> 628W