My son has a k55 (prior model) that he has used many hours a day for years. I was surprised how well the keyboard held up.
I use a Lenovo y510p at work and home and after 2 years installed a new keyboard as the tops wore too much for my taste.
It appears Castle Crashers capped the frame rate at 30 so the 820m would be ok at that.
My vote is the 5th Gen i7 in the Lenovo.
I narrowed down my search to three computers of similar prices, but I'm not very expert on this so I would really appreciate your opinion. One of them is a hybrid with ssd so I don't know if that's good. Here they are (it's in spanish but I think it's understandable)
I'll use it several hours each day for work (journalism) and general navigation, with intensive multitasking.
I'm mostly interested on the performance. I don't care that much about weight, battery, size or dvd capacity. I'm also not planning on playing big AAA videogames, I can do good with Trine or Castle Crashers.
Thank you for your time!