if you wanna play Twilight Princess, you need to get an i7 4700MQ; I wouldn't worry about integrated graphics too much (the 4400 seems to handle at least 1x IR okay, but a 750m would probably let you play at higher resolutions no problem.)
Any Intel U is going to be low power consumption, and thus not as good for Dolphin. I think Wind Waker should be fine on a 4500U at 3.0 GHz; but Twilight Princess is an absolute beast to run. If you're willing to give in on Twilight Princess, I think the 4500U will run the other games full speed? Maybe? I don't have a direct comparison, but I do know the 4700MQ will get full speed on Twilight Princess, especially if you use 4.0; which has the Twilight Princess hack. (MAYBE the 4500U could handle it on 4.0? I don't have enough CPU's benchmarked)
Any Intel U is going to be low power consumption, and thus not as good for Dolphin. I think Wind Waker should be fine on a 4500U at 3.0 GHz; but Twilight Princess is an absolute beast to run. If you're willing to give in on Twilight Princess, I think the 4500U will run the other games full speed? Maybe? I don't have a direct comparison, but I do know the 4700MQ will get full speed on Twilight Princess, especially if you use 4.0; which has the Twilight Princess hack. (MAYBE the 4500U could handle it on 4.0? I don't have enough CPU's benchmarked)