Hard to answer. Not only do you need to match the minimum specs, but preferably a little over. Also, not all laptops are created equally and even if they are, the way they are used makes a world of difference too.
In essence you don’t want to share your DJ laptop with other users and actually not even use it for another purpose yourself. A technically good way to have a separate DJ laptop without actually buying a separate laptop is using something called “dual-boot”. In this case you install a second instance of Windows. This is specifically different from just creating a new user in an existing Windows environment. When you (re)boot your laptop you will be presented with the choice of it booting as your family laptop (which remains unchanged) or as your (new) DJ laptop.
In the case of DJ laptop you want to remove everything you don’t need (there are quite a few documents and vids on optimizing a PC for DJ-ing), don’t add anything you don’t need and forego things like antivirus, networking facilities, screensavers, power saving modes and many other things.
You speak of a controller as if it has specific features. Obviously the controller is pretty much a dumb box, not worth it’s salt without software. So when you say a controller has nice effects, you are saying that it has the knobs to let you control the nice effects your software has.
Midi is the protocol that is used between your software and your controller to convey the control information. It is not a very heavy burden on a laptop in and of itself. So lag when controlling should not really be an issue. Where you CAN experience lag or – better term – latency is on the sound output end of things which is handled by the interaction between the sound card in your controller and your laptop/software. We have seen instances of more than adequately specced laptops having such problems. There are all kinds of settings you can finetune to get your system runnning dependably while having as little latency as possible.
What controller do you have now, what software do you use it with? What are your intentions (playing gigs, just playing in the privacy of your own room)? Stuff that helps us give you a good answer.
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