Unstable ASUS Z170 system. Boot fails or takes forever.

Hi all

So im a bit new in the overclocking community so please be gentle if I fail to give enough info or just seem like a noob Im a techie but a bit green when it comes to manual overclocking.
Some months ago I bought my first custom build system but it is very unstable.
What happens is that it often fails to boot. It just gets stuck at the ASUS splash screen with the "im busy" animation. And then it stays there for hours without booting. I have notiched that it happens mostly if I reboot instead of turning it off and then on... Maybe its just my mind making tricks on me.
I then have to kill the power (holding down the power button..) and start it again. Often with the result "overclocking failed. Please enter setup". I then enter bios, reset default settings and select the xmp memory profile. Sometimes it works and sometimes it dosent. But eventually the system boots. Just a matter of how many times I have to try and boot.
I happens maybe every 30% of the time.

Specs is as follows:
MB1151 Asus Z170 Pro Gaming
Intel Core i7-6700K <4.2GHz Quad LGA1151
2x DDR4-3200 8GB Corsair Vengeance XMP RAM
Nvidia Asus GTX1080 8GB STRIX
SSD Samsung 850 EVO 500GB M.2 SSD
PSU Corsair RM750x 750W 80+ Gold
CPUK Thermalright Macho Rev B

CPU-Z:

Doesn't look like from the pics that the system is overclocked but you start out by saying you are "green at manual overclocking." Are these boot problems happening at stock speeds and voltages? Things to try:

1. Reset the bios to "opimized defaults."
2. Clear the CMOS with the jumper (make sure there is no power to the board when you do this).
3. Flash the bios with the latest version
4. Make sure HD SATA mode is set to AHCI and not RAID
5. Fresh install of Windows

I note also that the Command Rate timing in the XMP column of the CPU-z SPD tab does not show 2T (which normally means it is 1T by default) but in the Memory tab your actual bios setting have assigned a Command Rate of 2T. You must also have two XMP levels for that RAM from looking at the SPD tab in CPU-z. Which one have you set it to in bios? Not sure any of that will make any difference but if you have more than two sticks of RAM you would want the CR to be 2T.

Now, on the other hand if the system is only having these problems while in an overclocked state it is likely some voltage is too low. Is the boot problem happening only in an overclocked state?

trents said:

Doesn't look like from the pics that the system is overclocked but you start out by saying you are "green at manual overclocking." Are these boot problems happening at stock speeds and voltages? Things to try:

1. Reset the bios to "opimized defaults."
2. Clear the CMOS with the jumper (make sure there is no power to the board when you do this).
3. Flash the bios with the latest version
4. Make sure HD SATA mode is set to AHCI and not RAID
5. Fresh install of Windows

Click to expand...

Thanks for your reply!
1. I always reset to optimized defaults and choose the XMP profile. This is how it currently is.
2. Have not tried the jumper trick but had the small battery removed today... and out back in of course
3. Checked for latest version today. All up to date.
4. ACHI activated.
5. Tried it. Didnt change anything.

I will try and look into the 2T vs CR thing you talked about. Need to do a little research about it first tough

It's not 2T vs CR. It's whether the CR is set to 2T or 1T. If nothing shows in that timing line in CPU-z it SPD tab it typically means that default is 1T. If your system is stable once in Windows the memory timings are not an issue.

Another thing to try is to make a Linux Live DVD and see if the system boots reliably from the DVD. That would bypass the SSD/SATA subsystem and suggest whether or not that was the issue. It is possible your m.2 sata SSD is bad.

Typically, default is 2T for ddr4. If it doesn't say 1T, I'd set it to 2T. Along those lines, I've never heard of 1 stick 1T trents. Where did you hear that? Chances are 1T will be fine... bit, default is 2T... even in ddr3.

Also, the latest bios for the board you list is from 3/3/17 (version 3202). Your screenshot shows version 2003. Are you saying you just updated it and are still having the issue?

To me, it seems like you are gett9ng past POST so then it's a drive or boot issue to me. Can you test the drive in windows using samsung magician?

EarthDog said:

Typically, default is 2T for ddr4. If it doesn't say 1T, I'd set it to 2T. Along those lines, I've never heard of 1 stick 1T trents. Where did you hear that? Chances are 1T will be fine... bit, default is 2T... even in ddr3.

Also, the latest bios for the board you list is from 3/3/17 (version 3202). Your screenshot shows version 2003. Are you saying you just updated it and are still having the issue?

To me, it seems like you are gett9ng past POST so then it's a drive or boot issue to me. Can you test the drive in windows using samsung magician?

Click to expand...

Where did I say that? What I said was that typically the CR needs to be 2T when you are running more than two sticks of RAM.

I misunderstood something. Apologies.

Side note...you can easily run 1T on 4 sticks. Doing so now, in fact.

He has 2 sticks and there is only one XMP profile according to his screenshots.

EarthDog said:

I misunderstood something. Apologies.

Side note...you can easily run 1T on 4 sticks. Doing so now, in fact.

Click to expand...

At least on AMD systems a few years ago when you went from two sticks of RAM to four you often had to change the CR from 1T to 2T to be stable at stock frequencies and voltages. Perhaps that was because the RAM manufacturers geared their JEDEC timings to Intel. And it also may no longer be true with newer stuff. And it also may be true that bumping up the DRAM voltage can offset that need as would purchasing expensive low latency RAM. But you yourself said that for DDR4 the default is typically 2T so that would seem to indicate that under stock conditions 1T is not the norm. My point was that running more sticks of RAM often suggests relaxing that timing to maintain stability.

Thank you for making your point clear in the above post. Note he has an intel system and this is now. As far as the timings... no idea. It's been 2t since ddr3 as far as I can tell. I've never had an issue going to 1T with 2 or 4 sticks on any intel platform. At stock memory speeds and timings, when I switched to 1T, I didn't add voltage... now overclocked memory and lower timings, I did have to up the voltage. In the end, the OP should leave it at 2T as THAT is default.

Also, the command rate being listed in SPD tab is hit or miss at best. Typically it's not there. Because it's not there doesn't mean it's different than default. That assumption can get you in trouble.

Anyhoo.. just waiting on some performamce and SMART data from the OP.

my guess is m.2 drive issues. I had very similar issues as op on my old c2d setup, and it turned out to be a bad sector which the os was installed to. stuck in the Windows loading screen forever. replaced hdd fixed it.

EarthDog said:

Typically, default is 2T for ddr4. If it doesn't say 1T, I'd set it to 2T. Along those lines, I've never heard of 1 stick 1T trents. Where did you hear that? Chances are 1T will be fine... bit, default is 2T... even in ddr3.

Also, the latest bios for the board you list is from 3/3/17 (version 3202). Your screenshot shows version 2003. Are you saying you just updated it and are still having the issue?

To me, it seems like you are gett9ng past POST so then it's a drive or boot issue to me. Can you test the drive in windows using samsung magician?

Click to expand...

My Z170A board was terrible about not booting every time and not recognizing XMP timings properly until I went to the latest bios, this is what I'd bet the issue is going to turn out to be.