Macbook Pro touchpad/keyboard lag issue

Hi guys,

I have noticed an issue with my early-2011 15" Macbook Pro and was wondering if any of you have experienced anything similar or would know the possible root cause of it.

My computer boots up and loads software alright, I do not experience any performance issues as such. However, whenever I stop using my laptop's touchpad and keyboard for a few seconds - ex. to read a line of text or to watch a youtube video - and then press a key or try using my touchpad, there is always a 1-2 second lag before keyboard/touchpad start working again.

I am running OS X 10.9.5 and have got 16 GB of RAM plus an SSD boot drive with plenty of free space - so I think it is safe to assume that this is not a sign of computer running out of resources.

I have tried restarting my machine multiple times and reset SMC once - that did not help at all.

Any ideas will be much appreciated!

Cheers
Alex