Is the intel i5 mobile 4200m processor good?

Solution
It should be fine for playing games. However, for games that makes use of more than 2 cores the mobile i5 will be a bottleneck. That's not to say performance will be bad in games using more than 2 cores. It just means that you would get higher performance with a quad core mobile i7 (MQ, HQ, MX models). However, a quad core i7 will probably set you back another $200 if it is an option for the laptop.

You should also know that choosing a more powerful graphics card will provide you better performance than a more powerful CPU. That means a mobile Core i5 + GT 750m will perform better than a mobile quad core i7 + GT 740m.
It should be fine for playing games. However, for games that makes use of more than 2 cores the mobile i5 will be a bottleneck. That's not to say performance will be bad in games using more than 2 cores. It just means that you would get higher performance with a quad core mobile i7 (MQ, HQ, MX models). However, a quad core i7 will probably set you back another $200 if it is an option for the laptop.

You should also know that choosing a more powerful graphics card will provide you better performance than a more powerful CPU. That means a mobile Core i5 + GT 750m will perform better than a mobile quad core i7 + GT 740m.
 
Solution