I am finding blocks with 40MHASH. on my test rig. with spreadminer #14.
Run it in benchmarkmode, if your oc is to high, you will get cpu validation errors. The netowrk difficulty has doubled and so has the price. As the price falls abit, the difficulty is falling as well..
My oc is not to high. I used this setting more than a month.
Also I checked it with benchmark , there is no cpu validation errors in benchmark, sometimes it show : found a solution , nonce $....
But there isn't any mine block within last 48 hours with 460 Mh/s!