Lag on Macbook Pro or Firefox?

[Art3mis]

I'm not sure what the problem is here.

For some reason in the last couple of days more specifically I've noticed my Macbook Pro lagging on Firefox, especially videos on YouTube, and webpages (text will lag when typing etc)
I'm not entirely sure whether this is just related to Firefox for the simple reason that if I load an App it takes a small amount of time to think before loading up. I don't know if this is normal when you have used your laptop for some time or installed stuff on it.

I cleared out the cache in any case, and cookies etc. Checking Activity Monitor everything *looks* peachy, but I'm not sure what to look for. In any case only 3% roughly of CPU usage is used so it can't be that.

Safari is a lot smoother, videos seem to run better, and it doesn't lag *as* much. Is this a firefox thing or is it possible it could be my Macbook?

I recently only got my Macbook Pro about three months ago. It's the 2012 model. I have 400GB of HD space remaining so no problems there. I have 4GB of RAM. Running Mavericks atm.

 

[Sital]

Have you tried restarting? That can fix many issues.

I use Firefox, and occasionally I notice a slowdown, but that has more to do with internet traffic as it always occurs on weekends/holidays. If Safari is fine, though, that wouldn't seem to be your problem. You can always try creating a new Firefox profile and see if that improves things.

 

[Art3mis]

Would creating a new profile affect my bookmarks or anything else? I've imported them into Safari for the time being as it seems to be running better.