Quick note for anybody using claymore who's hashing speed seems too low.
I'm on an RX480 8GB, was struggling to get over 350H/s, had tried a few miners and drivers.
I randomly tried to screw with the -h perimeter. If you don't put one it, it puts one in for you. I manually put in -h 800, and my hashes doubled to 620H/s. Then I tried -h 1024 and that's moved it to 650H/s. I will keep tweaking, but it's worth messing with if you're going slower than expected!
thank you for your post. It helped me a lot cause I was using the default -h 1800 but my 6 RX480 8GB were slow. So I changed to -h 800 and now they are about 620H/s.
Tomorrow will try -h 1024. Did you try any further tweaking?