I opened my PC to see the CPU just in case. It looks kind of weird in the bottom. It looks like a part is darker than the other one. Also, it looks it kind of dirty or something. I did not remember that my old i5 looked like this. I better show you pictures and you tell me if everything is ok. Everything, started because I could not get 4.0 by OC. Any recommendations or idea why this happened? Should I blame my CPU cooler? 
 

I tried. It does not work. The stain still there. I have no idea what is it. I am currently using the CPU but I am afraid I can damaged it.... 

 
That is normal.

Jet_Bl4ck87
I tried. It does not work. The stain still there. I have no idea what is it. I am currently using the CPU but I am afraid I can damaged it.... 

If the CPU works you should let it be. (any more actions at your own risk)
 
If it is flux residue - not an issue
I'm more interested in the couple of dark grey spots
 
However if your willing to go farther:
1) anti-static mat and wrist strap - follow ESD
2) large red eraser (no metal - not a pencil) lightly rub the back of the CPU till surface looks cleaner - gold plating is thin and soft
3) Wash with alcohol to remove residue
4) wait till completely dry before reinstalling CPU
 
IF the CPU socket fingers are also discolored at exactly the same location -- This May be electrical arcing.
 
Socket fingers can only be cleaned with the proper industrial electronic cleaner - per Mfg directions - usually well ventilated - follow ESD standards
 
Regardless if you try the cleaning above:
 
A) You may have over tightened your CPU heatsink, crushing the CPU socket, inspect for bent fingers.  Over tightening the CPU cooler crushing the socket can cause the fingers to move to a location on the back of the CPU - not intended.
 
B)  CPU heatsink Must be kept level, slowly (1/4 turn) tighten each of the fasteners in a "X" pattern, until heatsink is secure
 
 

Sell it and buy another if you aren't happy with it. Intel will just send the cpu back to you if it passes their testing.

Oh boy... it seems that I am really lucky to get this problem with the CPU. During the weekend, I will probably send it back to Intel. I am going to update you guys when if anything happens. 
Thank you very much for the help!

gtxjackbauer

Cool GTX
A) You may have over tightened your CPU heatsink, crushing the CPU socket, inspect for bent fingers.  Over tightening the CPU cooler crushing the socket can cause the fingers to move to a location on the back of the CPU - not intended.

 
I was thinking this could be it as it looks in different angles that there are two dings on it.  Granted it still works.

However, the CPU sockets did not bent. Maybe you are right, but I did not force them. Can I send it to RMA, anyway? Or what can I do?

My cpu had a few white spots on it too. Cleaning them didn't help at all. Cpu works fine and overclocks fine too.

Send it to Intel if you want.
 
It is totally up to Intel if this CPU was mishandled or is a "factory defect"
 
I will cost you shipping & time to find out what Intel will do.
 
It is only conjecture on our part. 
 
Have your retail receipt handy
 
GL

Jet_Bl4ck87

Cool GTX
Send it to Intel if you want.
 
It is totally up to Intel if this CPU was mishandled or is a "factory defect"
 
I will cost you shipping & time to find out what Intel will do.
 
It is only conjecture on our part. 
 
Have your retail receipt handy
 
GL

Is it possible that my CPU cooler is not working properly? My CPU temp in Iddle is 40-47. Also, I cannot believe I did such a big damage to my CPU. Maybe It was actually defective!

Your cpu isn't damaged. It works at stock clocks. Your basically rma'ing it because you don't like how it overclocks.

V84x4
 
I say it looks like water damage 

Discoloration comes from 2 things
Heat or water
 
Just my 2 cents
 
Regards, Rick

That's what I was thinking originally.

Haswell-EX look very strange looking from angle.
If we think on same, it's not possible to damage be like that... all traces are same perfectly.
 
Look upper corner... This is from some review.
 

 

 
 

If something is problem, than maybe this, but I doubt such small traces could be problem for CPU surface...
 

 
 
This can't be problem.
Or if this on bottom picture is not normal only Intel is capable to cause that...
For 2 pictures above I'm not sure, could be something, but CPU probably work normal.
 

 
 
 
 
 
 

Jet_Bl4ck87

I have a Corsair H75. Do I need to buy a new CPU cooler? I did not have time to send the i7 back to Intel yet. It is important to highlight that the CPU cooler have started to make a sound when it works. A friend told me that this is normal when they get old. Is this true?

You 100% positive the AIO is still sealed and nothing spilled on your components?  Whatever you do, if you RMA to intel, they'll find out if this was the case.
 
And no, AIOs don't get noisy unless there's a trapped air bubble,  they're on their last leg or its being run dry, basically killing itself because of no fluid from a broken seal.

gtxjackbauer

Jet_Bl4ck87

I have a Corsair H75. Do I need to buy a new CPU cooler? I did not have time to send the i7 back to Intel yet. It is important to highlight that the CPU cooler have started to make a sound when it works. A friend told me that this is normal when they get old. Is this true?

You 100% positive the AIO is still sealed and nothing spilled on your components?  Whatever you do, if you RMA to intel, they'll find out if this was the case.
 
And no, AIOs don't get noisy unless there's a trapped air bubble,  they're on their last leg or its being run dry, basically killing itself because of no fluid from a broken seal.

I am totally sure the AIO still sealled and it still full. I shook it I can feel a lot of liquid inside. 
 

Cool GTX
Use New TIM (thermal paste) to reinstall cooler
 
I like Arctic MX-4
 
Make sure to keep it FLAT, 1/4 turn per corner at contact, in a X patern
 
Top Left, then Bottom Right, the top Right, then bottom left
 
Do not tighten until the screws can no longer be turned - that's too tight - especially if the coil springs colaps until they touch coil to coil (google - coil bind = really BAD)
 
Noise:  Fan, pump ?
 
Make sure coolant is moving
 
Follow tipping directions to get the air out.
 
 

The noise comes from the pump. "Do not tighten until the screws can no longer be turned - that's too tight -" I did not know about that. So, if the pump have started to make noise... it means I already **** up my CPU cooler?