Minecraft and Black Ops 2 started lagging?

I have a laptop, DELL Inspiron 17R with:

Intel Core i7 3537U of 2.00 GHz (3.00 GHz with turbo boost)
AMD Radeon HD 8730M
8GB of DDR3 RAM
1 TB of hard drive

I have many games. I have Minecraft, Black Ops 2, and others. I've had this laptop for a year. I've never had lag in any game. Minecraft runs at 60-70 fps with the highest graphics settings. Black Ops 2 runs at 40-50 fps in medium-high graphics.

About 2 days ago Minecraft started lagging. It decreased to 40-50 fps. Black Ops 2 lags for like 10 seconds running at 10-20 fps, then it goes back normal. I checked and I have my laptop running at High Performance. All the AMD Drivers are up to date.

Check is your fan is on, (I know that seems weird, but it helps my laptop a ton when it's venting) make sure all your cores are active. Other than that, take it into a professional who will fix it.