R9 270X low hash rate question

Hi all, started with Zcash i have older card with 2gb of memory I am using latest claymore software but i am only getting 16.5 H/s when mining Zcash, my core and vram clocks are only 150mh, usage 100% but temps never go over 30c (i guess because of low stuck clocks).

Anyone have any ideas. I am new with zcash.