Laptop gets hot when screen times out

My laptop starts spinning up the fans and getting hotter onces the screen auto times out. When I wake it up, the core temp is around 160-170F, and drops almost immediately after swiping across the touch pad to wake the screen. The moment it wakes, CoreTemp shows it running at full clock (2.2 GHz i7-2675QM), but then it immediately drops to 800 MHz and goes to idle temp around 125-135F. Any ideas why it may be ramping up like this with the screen off?

EDIT: It's a Samsung 7 Series with W7U, 8GB RAM, 120GB SSD, and 1TB HDD.

TYIA!

Redsox when I first read this my immediate thought was perhaps the monitoris powering down because the machine is too hot. So I am assuming yo havechecked all the vents and outlets for dust etc? Is this the same as a previousmodel where the get to the HDD you can access the CPU and GPU?? If so have ordid you check the state of the thermal compounds because those temps you quote are reasonably warm for my liking especially idle see ARK | Intel® Core? i7-2675QM Processor (6M Cache, up to 3.10 GHz) the Tjunc is 100C and your idle is 52C and the other 78C which I would expect if you were running a heavy - ish game

Ok mate now I am pretty ok with Toshiba stuff and Samsungs I have never had to deal with I saw a Youtube on the model before yours but could not see how the heatsink/s and heat pipes were held onto the motherboard but in the Toshiba's most of then you only need to tighten down the heatsink/s - there will be two CPU and GPU - just enough to take the slack up on the springs. again The Samasung might have a different system but what ever you do do not over tighten them.

Now for cleaning you can use alcohol but this is the very best Arctic Silver Incorporated - ArctiClean as it cleans and prepare the surfaces real good. The compound also Arctic Silver Arctic Silver Incorporated - Arctic Silver 5 What I do is to get a vinyl glove and thinly smear the compound (after cleaning) on both surfaces then a spot about the size of a grain of rice - no larger - then fix the heatsink/s down again.
If you happen to touch the surface before with you fingers - reclean as your skin has acids and the like on it but I am a bit pedantic it really is up to you.
In the pics it gives you a rough idea of what those chips will look like and while you are at it take time to reseat the RAM sticks and / or clean them.

SLOTCLEANING

Now as for the slots to clean them use astrip of old credit card about 1/2 inch wide nip the corners off one end - preferably round them offhold apiece of thin lint free cloth over the end dab on some form of alcohol - isopropyl alcohol (what we swab the skin with before an injection) is good and GENTLY swipe along the slots.

This can also be done for the GPU slot/s.

Red I meant to add when doing laptops I do the work by placing a large white bath towel taped to the top so that if you drop those small screws they don't bounce off the top onto the floor where they often get lost the towel stops that happening and you can see them real easy. :)