Question Computer won't cold boot when RAM XMP is enabled ?

[m4a1drumro11]

I have my CPU overclocked to 4.8Ghz and my 32GB of ram overclocked to 3200Mhz. I can restart my computer fine and run my computer fine. My computer passes all Prime95 tests. If I shut down my computer and try to start it back up(cold boot) it won't post. The motherboard will light up but none of the diag lights will turn on. I can only get the system to turn on normally by unplugging the power cord and holding the power button to drain the system and then it will boot fine. The only way I have gotten the computer to boot normally is by underclocking the RAM to 2500Mhz. My RAM is rated for 3200Mhz so why cant I run it at that? It makes no difference if I have 1 stick of ram or if I revert my CPU to base clock. I tried turning the DRAM voltage to 1.36v and that made no difference. I have disabled fast boot and quick boot in bios. I have disabled fast boot in the OS power settings. I found out that 2500Mhz was the sweet spot but lowering the clock speed and rebooting the computer until it would boot normally from a cold boot. Are there any other settings I need to change on my mobo to make this work?

Issue:
*can't cold boot when ram is set above 2500Mhz

Measure taken:
*disabled fast boot and quick boot in bios
*disabled fast boot in OS
*tried 1 stick of ram
*tried CPU at base clock

Temp fixes:
*run ram at 2500Mhz
*pull power cord in order to boot


OS: Windows 10 Pro x64
CPU: Intel i7 7700k 4.8Ghz
Mobo: Asus TUF Z270 MK2
GPU: Asus ROG AE8 STRIX-GTX1080-A8G
GPU2: Nvidia GTX 1080 FE 8G
RAM(A1xB1): 2x Gskill DDR4 3200mhz (16GB Duel Channel)
RAM(A2xB2): 2x Gskill DDR4 3200mhz (16GB Duel Channel)
SSD:Western Digital 2TB WD Blue 3D NAND(OS Drive)
SSD: Western Digital 2TB WD Blue 3D NAND(Games)
SSD: Samsung Evo 860 1T (Games)
HDD1: WD Blue WD10EZEX 1TB 7,200 RPM (Main Storage)
Monitor: Asus VG248QE 24" 1ms 144hz
Monitor2: Asus VE248H 24" 2ms 60hz
Monitor3: Asus VE248H 24" 2ms 60hz
PSU: EVGA SuperNOVA 850 G3 850 Watt 80 Plus Gold
Sound Card: Asus Xonar DSX 7.1 PCI

 

[Karadjgne]

In bios, put VCCIO and VCCSA to 1.2v, those are the memory controller and memory transmission voltages. If the memory controller itself is a little on the weak side, higher speed ram can cause errors, and a failure to boot.

Check the cpu cooler fitment. Loosen it up and then tighten it back down sequentially in an X pattern/back and forth pattern, only a turn or so once touching, then a half turn to snug. Don't tighten one screw before another as it can and does put undue pressure on the cpu in the socket, which can and will affect ram/memory controller especially.

 

[zx128k]

Sounds 100% like a training issue for the RAM. There is a Q-LED on the motherboard. There is a CPU-LED and a DRAM-LED. I would check which one it stops on. Many motherboards have different support levels for many RAM kits. That you can't boot with one stack at 3200 would implies the motherboard has issues with that kit at 3200. Given that you can boot at DDR4-2133/2400 and 2500 this would imply a motherboard or IMC issue. Timing problems etc.

My motherboard doesn't support 4xDIMMs at speeds above DDR4 3600. It was hell getting DDR4-4000. Increasing VCCIO and VCCSA can help. They help me get 100% stable and be able to dial in the timing manually. It would try timings that are not as tight as the xmp profile and see if relaxed timings help the kit work. Normally if a kit will work it will boot and the system is unstable. If the timings are too tight, then the system wont boot. To get DDR4-4000 CL15 I had to tune everything manually.

Also increasing the CPU clock speed increases the voltage requirements of vccio with my cpu.

Even so there is a point a system will never boot, the fact you have 4xDIMMs makes getting higher frequences all that harder. With my motherboard, DDR4-4400 is possible with 2xDIMMs but with 4xDIMMs DDR4-3600 is possible. The BIOS will put massive amounts of VCCIO/VCCSA into the CPU to try and get the system stable. I had to update the bios just to get above DDR4-4000 to boot. Then my system was not stable. I had to tune some very advanced DDR setting for the timing for the motherboard because the RAM and the IMC couldn't detect them correctly everytime.







This was a pain for me to do and this let frequencies upto DDR4-4200 to boot. I have not tried above DDR4-4000 because it was hard work getting DDR4-4000 to work. I was learning as I went. There is always a point were the system will never boot.

If there is a mounting issue this can cause issue with RAM. So what Karadjgne states is what I would do if the system wouldn't post at all. I would reseat the cpu and make sure the pressure is even and check for bent pins on the motherboard.

 

[m4a1drumro11]

Hi All,

I was able to resolve my issue by reflashing my BIOS. My bios was on 1301 but I flashed it again to 1301 and the issue went away. My last time I did the update something must not have gone well or flashing the bios again changed some settings that resetting CMOS did not reset.

Thanks for your replies.

 

[zx128k]

Good that you got it to work again.