OMG, you do not even understand, what we are talking about here. The risers that you are suggesting have ONLY 1x link speed between GPU and motherboard. But we need 16x link speed risers, for getting max hashrate out of 4GB video cards with lolminer.
So you guys really believes in this lolminer 4gb magic touch? I don't believe in that crap because it's cheating and unrealistic too, anyways I'm glad that 4gb gpu owners can still make good amount of money out of the old cards, enjoy it while it lasts