You should be aware that your GPU is extremely unreliable in creating shares and you should figure out your rejection rate. I believe 10H/m is the standard for each 270x card.
Just make sure you're not using the GPU while it is mining.
Thanks for interest. I have relatively low rejection rate and I do not use computer for anything else - even monitor is switched off most of the time.
10 H/m is normal for one 270x card, but I am using two. As I have written, both of them report to work on this rate and pool reports 20H/m on my wallet address. The problem is that I get paid half of expected coins.
Are you using GPU miner on MMC2 through 1gh.com pool? Is your earning as calculator predicts?