This might be one relative advantage of the difficulty of mining bitcoin vs. dogecoin, it's not worthwhile to mine bitcoin without dedicated hardware.
I checked it for fun. Just roughly estimating:
If ignoring power consumption, scrypt-based coins (Litecoin, Dogecoin) are currently about 40-50 times more profitable for GPU mining than SHA-256 (Bitocin) based. CPU mining is ~125 times more profitable in favour of scrypt.