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i7 6700k and Z170 Pro Gaming = highly unstable

MaccieD
Level 7
Last week I bought a new CPU, motherboard and RAM.
It ended up being a i7 6700k, a Asus Z170 Pro Gaming with G.Skill Ripjaw IV 16 GB DDR4 2800Mhz set.
Installed everything, did a first start = everything was worked fine.
Next did a BIOS update, update went without a hitch so no problems there.
Then restarted and started tweaking the CPU and RAM.
Got the i7 6700k running at 4.4GHz on all cores and got the RAM to work at XMP profile.

It all was working fine until last Saturday when I change the CPU cooler for a new one (a Scythe Fuma)
That's when excrement hit the air circulation system.

First the PC didn't want to start up, it hung before it finessed POST.
Check the LED's on the motherboard and it hung on RAM.
Next I did a hard reset on the BIOS (removed the BIOS battery for a couple of seconds) and after some doing finally got the motherboard to except the RAM modules again.
Checked the RAM modules with memtestx86 and they passed the test without problems.

But since then I have not bin able to get the system stable.
Not with a slight overclock, not even with all optimal values.

9 out of the 10 times when you start the system cold it will not boot, it'll hang during POST.
When you reset (push the power button 10 seconds and start again) it'll show a overclock fail.
When the system does start as it's suppose to and you restart it (even after a couple of hours) 9 of the 10 times it will hang during POST.
Another thing which is noticable is when the system starts it takes a long time to get passed POST

What I found out is that for some reason or another it doens't seem to like the XMP profile.
Next, even with the optimal values from the BIOS loaded (so no overclock what so ever) , when you do a benchmark run with XTU it puts way to much voltage on the CPU (1.44v when between 1.35 and 1.4v is the maximum for 6700K's)
Because of the over voltage the CPU gets it will heat up to 70 degrees within a couple of minutes, the PCH will heat up to 70 degrees within a couple of seconds
It even over voltaged the RAM modules (1,5v will the only need 1.2v)

The things I've done till now :
Check the motherboard and CPU for burn marks, if the CPU was bent, if the CPU was seated on the motherboard correctly.
Loaded XMP, put a fixed voltage for the RAM modules, put CPU Core/Cache voltage on adaptive.
Manually input the RAM values (so not using the XMP profile)
Put USB legacy on disabled
Tried to do a rollback with BIOS to version 1904, the motherboard didn;t accept it, said the BIOS was incompatible with the motherboard.

All of this is hit and miss :
Sometimes the system starts without a hitch, most of the times it will hang during POST and when you reset it will show overclock fail

When the system does startup normally it works fine in Windows and there are no problems when you're gaming.

I understood from reading the forum the last couple of days that a long POST boot up is quit normal for Asus Z170 motherboards

Does anyone have any idea was wrong here ?
I thinking that either the motherboard or the CPU (maybe both) are failty...


Here's my setup :
Intel i7 6700K
Asus Z170 Pro Gaming
G.Skill Ripjaw VI 16GB DDR4 2800Mhz
Gigabyte GTX 1080 Gaming G1
Creative Soundblster Z
Intel 750 800GB PCI-E SSD (boot and games disk)
1 4TB Western Digtal 5400rpm harddisk
2 6TB Western Ditial 5400rpm harddisks
Corsair RM750X power supple
16,873 Views
23 REPLIES 23

Nate152
Moderator
Hi MaccieD

My 6700k draws 1.44v at default settings too, you can manually set the voltage to 1.20v.

The freezing and overclocking failed message is likely instability with your ram, check to see the timings and frequency are correct.

If all looks good and you still get freezing try setting the Dram voltage to 1.25v - 1.30v and see if it boots normally.

Since the problem happened after installing your new cooler it may be too tight putting uneven pressure on the socket, you could try loosening your new cooler a touch.

MaccieD
Level 7
Thanx for you response Nate.

I've already checked the timings and frequency and the were correct>
Even inputted them manually.
It didn't make a difference

Gonna check the cooler now 🙂

Nate152
Moderator

Removed the CPU cooler, applied new thermal grease and reinstalled the cooler.
Now it has a little movement, it can slide a little over the thermal grease.

It didn't solve anything, it only made things worse.
During start up, the system hangs during the RAM test.
It will handle 1 RAM module, but not both.
Just running 1 RAM module and the system boots, using them both and it hangs during the RAM test in POST.
I've tried putting them in A1/B1 and A2/B2 but it doe'sn't make a difference

I've managed to get it working once, run memtestx86 to check the RAM modules and both passed without trouble.

So by the look of things it's the memory controller that is failty (read dead)

[update]
Got the system running with both RAM modules, (installed in slots A2 and B2) and running XMP profile
Gonna run some test's now (realbench, xtu etc)

While the PC worked for about a hour, when you shut it down for more then 15 minutes, the hole BS starts again.

Hangs during POST (LED's on motherboard report it constantly switching between CPU and RAM) and not working with both the modules unless you pull one out, put BIOS back to optimized settings and start over again

Nate152
Moderator
It's only recommended to update the bios if you're having compatibility or stability issues, since everything seems ok I would leave it as is. Maybe you accidentally bumped one of the ram sticks when installing your cooler.

As far as adaptive mode, what you want to do is find the lowest stable voltage in manual mode then switch to adaptive mode and enter in your voltage in the "Additional Turbo Mode cpu core voltage" and run a stress test. While the test is running, subtract however much the voltage is overshooting and enter that in the negative offset.

Nate, it's not working at all.

It worked for about a hour, in which I was able to run realbench.
But after shutting the system down and starting it up again about 10 minutes later it all started anew.

Nate152
Moderator
All right

Clear the cmos with the two pin jumper, if you're not sure how to do this take a look in the manual.

Let me know when you get it booting again.

MaccieD
Level 7
Cleared CMOS, still didn't want to boot.
Took out 1 RAM module, then got it started.
When it doesn't want to boot you constantly see it sitching between CPU and RAM when you look at the LED's on the motherboard.

I'm putting it aside for now, it's starting to get on my nerves :@
I'm gonna take the system to the shop were I bought the CPU and motherboard so they can diagnose if it's CPU or the board that isn't working propertly
.