For some reason every time I start mining it goes ~16 Mhash/s for like 20 seconds and then it drops down to 400 khash/s
Bitcoin mining on a laptop isn't probably the best idea...
You're right, it's a bad idea because you're pretty much forced to mine with your CPU if you have integrated graphics, which can't mine for shit. I've an i5 3570k overclocked to 4.6ghz and I would be lucky to get a few megahashes/second, but with my 7870 I get a steady 410 megahashes/second
Actually I've made $3 after less than 2 days of mining.
Thing is I only have been mining nightly, once school picks up I'll probably mine daily