Hey Thirtybird I tried to mine with your cpuminer,I have intel i7 and I use minerd corei7! When I use -a scrypt -o stratum+tcp://yac.coinmine.pl:9088 -O WorkerName:WorkerPassword I get actual processor power which is 25kh/s but accepted shares are invalid but when I use -a scrypt-jane -q -o stratum+tcp://yac.coinmine.pl:9088 -O worker:worker_pass shares are valid but my power is 0.07kh/s ! please help!
If you use the '-a scrypt' flag, you're computer is mining using the scrypt algorithm instead of the scrypt-jane algorithm. YAC uses scrypt-jane, so you will have to use the '-a scrypt-jane' flag to have valid shares. The decrease in mining speed is normal. YAC uses the 'N-factor' which increases the hash length, and helps keep the coin resistant to ASICs and other specialized mining software.
If you use '-a scrypt-jane' and you're still not getting accepted shares, try using the '-a yacoin' flag. I know some of the miners use this instead.