Why do you want to use such GPUs? They are mostly useless. Any GPU costs same as much as profit it brings. Try to search AMD RX470-580 with 8GB memory at least. Or may be 1060 with 6 GB.
In another way you can buy 3GB or 4GB GPUs, but you can`t mine the most profitable coins with them.
funny thing. I picked up a pair of AMD Firepro S9000 (6GB ECC RAM) passively cooled gpu's for $175 off of ebay. Popped one of them in to a test rig, fired up lolminer and off and running @ 23 MH/s. They do run hot currently, 74c. So I am redoing the thermal pads and paste on the second card. This card is the pro version of the HD 7950. But it was cheap, and I was interested to see if it would actually work. If anyone knows if I can control voltage and clock speed via parameter setting with lolminer, please post a link to the documentation.
Thanks,
JimS2321
Are you mining Ethereum or Ethereum Classic?
HD 79XX series hashrate dropped when increasing
Dag file, and so they were sold. Although these cards had 3GB of memory, except for the HD 7990.
These cards were very hot, if I'm not confusing anything, then they were heated up to 90 C. After 100 C, my farm turned off.