I have the same issue for a long time and until now I can't find any solution yet.
It's fixed with latest Gminer. Thanks arielbit!
Oh it seems it's already fixed with gminer what driver you currently use?
Let me try gminer thanks.
Opppsss.... I tried today it seems the problem still the same with low hashrate...
What driver you currently use? Can you share your bat file I just want to try your settings?
drivers are 430.86, 451.67 and 460.89 all of these works
my .bat is very basic
miner.exe --algo ethash --server asia1.ethermine.org:4444 --user yourETHaddress.workername
you might be using 4gb system ram, make it at least 6gb .....this issue was already long ago too, this might be your issue.