So, I had a bunch of 7990s left over from the litecoin mining days, and these cards came with a 3 year warranty.
With under 1 month of warranty left, one of the cards died - so went to get it claimed under warranty. They couldn't fix or replace the card, so they suggested giving me a 390X. I obviously refused and wanted something with equal or better power. A few days later, they called me back and gave me a brand new HIS 295x2 as a replacement. For free.
The 7990 alone was doing close to 40MH in Claymore (almost 20MH per GPU)
The 295x2? Lol... overclocked to the max, it hit almost 69MH! (~34.5MH per GPU) but the best thing about this card is the water cooling. I'm mining at the speed mentioned above with a cool 66C.
Its a shame these cards were so ridiculously expensive when they were launched, but if anyone can pick them up used, go and do it. I really want to see someone make a 4x 295x2 rig
Comments
7990 was too loud and run hot most or the time.
Rx480 undervolted will give better efficiency but 295x2 is way better than any 370, 380 or 390
Don't believe any of the fantasy with 600+ watts.
First, it is not that power inefficient. You see, a 2x295x2 rig is the same 4 x 290x. I can use a 1200W psu to run 2 295x2, but cannot run 4 290 with the same psu (even my pcie cable is not enough).
Second, since 295 x 2 is water cooling, it cools very well. Instead of 7990, we do not need anything special for cooling. Currently I just plug the two cards directly into the motherboard without a riser, and close the enclosure, since I put my pc in my office to get free electricity . It cools very well (never goes above 70C).
I run currently, -45mv, 1040 core with stock mem.
I could push it higher, but I don't wanna stress the card out too much. Its been happily running for 2 days now at the current settings.
@nathann how did you undervolt your card?
I only undervolt because mine thermal throttles like a mf.
Going to try get better airflow this week and can hopefully squeeze out a few more MH/s