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