I've got a medio 2011 27" iMac (i7 3,4 Ghz) with a 2 GB Radeon 6970M graphics card. When I mine Litecoins with the CPU, I get something like 40 kh, and when using the GPU, it gives me about 50, is that really all such a machine can do? I know that it is a Mobile gfx, but thought that GPU should be much faster than CPU mining? Tried fiddling with the settings in BFG Miner, but nothing gives me more than that speed (and setting the Intensity over 13 gives a lot of errors). If this is the speed, then it makes no sense at all mining, since the cost of electricity is way more than what I can get from my share of a pool!
Also, this i not a MacMiner question in general, but in the pool I'm in, the top user has a total mining speed of 671819 KH, how is this possible, is he having access to thousands of machines?