New PC Build Intermittently Won't Post

[cutelz]

Hello, I'm hoping that someone in here might be able to give me some guidance. I just built out a new PC and I'm having a strange problem. Sometimes the PC won't post. If I press MemOK on the mobo, it will post right up. When it's running, it runs fine without any noticeable issues or lag.

When I first bought the components, I accidentally purchased a 7th series CPU and had issues trying to get it to start up because of that. Once I got the 8th series installed it came up no problem. Then I discovered that one of my RAM sticks was dead. The warranty covered that and it was replaced.

I haven't tried too many things because I honestly don't know where to start. I've checked each stick of ram by itself, but one of the problems seems to be that once it posts, it will be fine for a little while. But if I leave it sitting overnight off, it won't post up again the next day. This makes troubleshooting a little difficult as I sometimes won't have immediate feedback on if my changes did anything. I have also tried securing all of the connections to all of the components and moving the video card into a new slot.

I did seem to have some brief success when I disabled fastboot in the BIOS, but the problem came back again pretty quickly.

Another problem that I face that may or may not be related is that the computer will not wake up from sleep. I have followed the online recommendations for turning off certain Windows 10 features, but none of that seems to have worked.

I am a little scared about modifying voltages on the motherboard as that would be my first time doing anything like that, but I really need this computer to work properly as I spent a LOT of money on it. Any advice would be GREATLY appreciated. Thank you so much for reading.


Build Specifications with links to their Newegg or NVIDIA pages:

Tower
Thermaltake View 71 RGB 4-Sided Tempered Glass Vertical GPU Modular E-ATX Gaming Full Tower Computer...

Motherboard
ASUS ROG Maximus X Hero (Wi-Fi AC) LGA 1151 (300 Series) Intel Z370 HDMI SATA 6Gb/s USB 3.1 ATX Inte...

RAM (x2)
G.SKILL TridentZ RGB Series 16GB (2 x 8GB) 288-Pin DDR4 SDRAM DDR4 3200 (PC4 25600) Desktop Memory M...

Processor
Intel Core i7-8700K Coffee Lake 6-Core 3.7 GHz (4.7 GHz Turbo) LGA 1151 (300 Series) 95W BX80684I787...

CPU Cooler
Thermaltake Floe AIO Riing RGB 360 TT Premium Edition PWM TR4 LGA2066 Ready Liquid Cooling System CL...

Power Supply
EVGA SuperNOVA 750 G2 Power Supply - ATX12V/EPS12V - 110 V AC, 220 V AC Input Voltage - 3.3 V DC, 5 ...

SSDs
SAMSUNG 860 EVO Series 2.5" 500GB SATA III V-NAND 3-bit MLC Internal Solid State Drive (SSD) MZ-76E5...

Graphics Card
NVIDIA Titan XP

[Heini]

I'll be the first and maybe the worst but...... "Another problem that I face that may or may not be related is that the computer will not wake up from sleep. I have followed the online recommendations for turning off certain Windows 10 features, but none of that seems to have worked."
Turn off sleep mode for a day or two and see if the helps.
Reset bios and Win to defaults first.

edit to add ... your component selections seem to be solid choices leading me to believe that it's Windows/bios/software related.

[brkkab123]

You said you got the wrong cpu at first.
When you put the right cpu in did press F5 in the UEFI to load optimized defaults, so the new cpu would be detected ? Did you then press F10 in the UEFI after any changes you made?
Did you repeat both of those two steps again after having the 2 good ram sticks?
Did you ask the ram manufacturer why they only replaced the bad ram stick and not the ram kit?
From past experience that one's important, too.
Example a few years ago I got one set of G-Skill Ripjaws ram for a PC I built. A few months later I ordered a 2nd kit of G-Skill Ripjaws ram of the identical speed as the first set.
I found out the newer kit had different timings than the first kit, so I had to send the 2nd kit back and order a single 4 stick kit (2 pairs in the same package with the same timings).
1st and 2nd ram stick you now have may very well have slightly different timings.
Last, but not least have you reactivated Windows since the correct cpu was installed?
Different cpu or motherboard means new PC to Microsoft.

[brkkab123]

Almost forgot this one, did you download and install the newest UEFI and drivers from Asus for your mobo?
If not, do it immediately.
Never use any hardwares driver cd, always download and install the most recent UEFI, drivers and any hardware software you're gonna use from the manufacture/s and use it, not the included always old driver's/software/UEFI cd in the hardware's boxes.

[chevell65]

At the very least you need to set the memory voltage to 1.35 then use either default memory setting 2133Mhz or set XMP memory profile.

[cutelz]

I went to try brkkab123’s suggestions and got a CPU overtemp error. It was at about 80°. I’m going to check my coolers commections, reseat the CPU, and hopefully solve this problem. I suppose there’s a chance this whatever this error is may be same one causing the posting problem 😧

I’ll reply back here oncw I make some progress. Thank you for taking the time to reply it is extremely helpful. I’m feeling super lost at the moment.*

[cutelz]

brkkab123, thank you for the suggestions. I tried doing the optization thing in the BIOS like you suggested. I haven't had a load problem since, so I'm very hopeful that this worked! I will bump this post back up if it ends up not working out, but thank you so much for replying! It really gave me some direction 😄

[kkn]

let me guess, you did buy 2 ram kits? ( AKA 2 packages of 2x8 gig of memory sticks ).
pull out all the ram, and divide them in to the packets hey belong to, and only have ONE ram stick in the mobo and try and boot up then.
see if you have the same problem.

if you miss match 2 ram kits you WILL ask for problem on intel chipsets since it is picky on this.
always buy ONE kit of the amount or memory sticks you need.