i7 6700k boot loop

[midadvancedone]

Hi.
Today I decided to start building my PC which will replace my 3 years old pre-build one. I assembled it without drives and external graphics card since I dont have one yet. When I pressed the power button on the case the CPU fan spinned and the back case fan lighted up for about 3 seconds and after that the back case fan's leds turned off and both fans stopped. In less than a second this process repeated itself over and over. I waited for more than 10 minutes and realized it was a boot loop. The PC didn't even got to the POST screen. I checked the CPU pins and none of them were bent, plugged out the 4-pin CPU power cable and plugged it back in (same with the 24-pin motherboard cable). Also swaped out the PSU for SilverStone SFX form factor (model is ST-45SF-G) and cleared the CMOS by connecting the two pins labeled as CLR_CMOS with my magnetic screwdriver for 6 seconds. None of this helped. I noticed the CPU Status LED turns on and off in sync with the fans. According to the manual this means problems with the CPU however I don't think the processor is bad.
Also I double-checked and there is nothing metal touching the motherboard. All components are plugged in correctly and none of the hermal paste have leaked on socket or the motherboard. I builded this system on a antistatic mat with wirst and grounding cable included so ESD isn't a problem.
The only things that are connected to the MB are the aforementioned cables, front panel connectors, speaker (which dosen't beep despite being correctly plugged in), CPU fan (plugged in correctly mind you) and two 3-pin fans that come with the case. Here are the parts:
CPU: Intel i7-6700K , used
MB: Gigabyte Z270 Gaming K3 rev. 1.0
CPU Cooler: Cooler master Hyper 212 EVO
Case:InWin GT1 (this case have ATX standoffs already integrated into motherboard tray so there is no need to install them)
PSU:Antec Neo HE550
RAM:Kingston 16GB DDR4 2133 MHz CL 15 (KVR21N15D8/16), pluged in the slot that is the furthest away from CPU, used

Video of the boot loop:
https://drive.google.com/open?id=1ppO6yTWfXxXeRhu-yHH688qkMsTvANSC

 

[alexoiu]

Hi, Try disconnecting all cables/components from the board, but CPU and CPU fan. Connect both 24 and 8 pin power cables. Start the board and see if still the same.

 

[midadvancedone]

Hi, Try disconnecting all cables/components from the board, but CPU and CPU fan. Connect both 24 and 8 pin power cables. Start the board and see if still the same.

Removed the ram stick and case fans. Also checked if I connected the speaker correctly (the arrow on the plug goes on the black plus printed on the speaker socket so its correct). Also did not plugged in the reset switch. Still nothing.
But I noticed the DRAM status LED is off despite no ram being inside 😛
Kinda like the MB is stuck on CPU test before even moving on to other components.
Also here are the CPU pins - none are bent:
https://drive.google.com/open?id=1ObE6jE2jYIblBg86pU6DUCsXCu1Ek092
Forgot to mention RAM stick was also used.
And just in case I made a photo of the backside of my cpu:
https://drive.google.com/open?id=165eUcJbTHwEmdcgnL2yROTBXoP4rqU4Y

 

[alexoiu]

Try testing the board outside the case. Check also the CPU cooler backplate if correctly installed.

 

[midadvancedone]

Try testing the board outside the case. Check also the CPU cooler backplate if correctly installed.

I dont have the power switch to plug in. As for the backplate it was correctly installed (only the green parts are touching the motherboard). Tried touching the pins with screwdriver but dosent seem to work.

I also measured the standoffs that are welded into the motherboard tray - they are not the reason for the boot loop. I'm starting to think the CPU I bought in July was either bad to begin with or got damaged in shiping. Unfortunatly I was unable to test it back then.

 

[alexoiu]

No other idea, than RMA-ing both board and CPU.

 

[midadvancedone]

Cant find the proof of purchase for any of them ;(

EDIT: I found what appears to be the cheapest CPU supported by this MB (Celeron G3900). I'll see if I can get one and test if the problem lies in CPU. I handled the MB with utmost care (like every other build I did), installed the cpu, cooler and ram on antistatic mat so I dont think its the motherboard. A quick look at the Gigabyte support website reveals all processors that are supported by this MB will work without BIOS update so another reason for boot loop goes out of the window.

EDIT 2: I've got my hands on that Celeron G3900 (not really good for gaming btw, just bought it to see if this is a bad cpu or mb), put it in the motherboard and after like 12 seconds it went past POST with a single beep form the speaker and directly to the BIOS screen. So it was a bad cpu after all. I'm gonna contact the person who sold me that processor so I can get a refund. Thank you alexoiu for your help.