There's nothing that unusual about the HD 650 in terms of being an electrical load for an amplifier to drive. There's not any magical difference between dedicated headphone amplifiers and whatever is in your laptop. They both attempt to generate and maintain an electrical output that makes headphones drivers move and make sounds. It's just a matter of different electronics having different capabilities, performance. The consequences are that a dedicated headphone amplifier might be shinier and fancier. Oh, and they may have better performance, probably are capable of higher output power with all kinds of headphones.
By better performance, I mean lower distortion in some sense, less crud that's not supposed to be there. Or sometimes, for dedicated headphone amplifiers, people go for higher distortion in certain ways to enhance the sound (maybe, YMMV).
Some of the potential issues with cheap integrated headphone outputs include high source output impedance, low output current capability, maybe a higher noise floor, etc. are not problems (or not as big of problems) when using high-impedance headphones like HD 650s. You just run into the output voltage limitation, so it can be too quiet, even at the loudest setting.
You can break them in—for what it's worth—with the laptop if you want.
Edited by mikeaj - 9/10/12 at 3:38pm