Most likely need to bump some voltages up to get things stable. Specifically vsa/vccio. Try 1.2 to 1.35v on each.

Have you try reset default your bios setting back default and then try again test with your memory?

my_hobby

coolmistry
Have you try reset default your bios setting back default and then try again test with your memory?

Many times. Sometimes, even due to unsuccessful overclocking, it was necessary to reflash the BIOS.

I hope you have latest update BIOS to 1.18 for Classified K
Try overclock memory without CPU? 

 
I have the same board you do, and lately I've been thinking of OCing my RAM a little bit .  First, I note that EVGA only rates the Z370 Classified K at DDR4 4133 OC,
so I'll have to stay well under that for an easy OC .  I plan to study hisevilnesses' DDR4 overclocking guide for help, cuz I'm dum ;)
https://www.hisevilness.com/articles/technology/overclocking-guide-for-ddr4-ram.html?showall=1
I will also use the EVGA QVL list, and Intel XMP profile ( 2.0, I think ) table https://www.intel.com/content/www/us/en/gaming/xmp-for-core-processors.html
to get some starting points reference for speed, voltage, and timings .
It should work good for a light to medium OC because I have OC friendly Samsung B-die IC memory modules . https://benzhaomin.github.io/bdiefinder/
The B-die finder works well for RAM contemporary to the Z370 chipset .  Also, I removed the plastic from my RAM heat spreaders, and have a case fan on the RAM,
customized, bro :)
 
P.S. I don't have any luck using the search function on the EVGA OCing forum .  Too bad .
 
Hope you get your RAM to high, high speeds !
 
 
To the Moon !
 

When overclocking RAM on the Z370 Classified K and not using XMP you will need to enter some settings manually, such as;
 
CAS Latency
RCD/RP Latency
RAS Latency
tFAW (Four Activate Window - the board can usually train tFAW ok with 2 DIMMs, it may need to be set manually if using 4 DIMMs)
CWL (CAS Write Latency - set this 2 below your CAS Latency)
RFC (Refresh Row Cycle time)
 
Some suggested (very loose) timings for each increase in RAM speed, just to see if the board will POST (these numbers are for 2 DIMMs);
 
3700 = 17-17-17-39 (CAS-RCD-RP-RAS), 41 (FAW), 15 (CWL), 642 (RFC)
3733 = 17-19-19-39 (CAS-RCD-RP-RAS), 42 (FAW), 15 (CWL), 655 (RFC)
3800 = 19-19-19-39 (CAS-RCD-RP-RAS), 45 (FAW), 17 (CWL), 666 (RFC)
3866 = 19-19-19-40 (CAS-RCD-RP-RAS), 47 (FAW), 17 (CWL), 677 (RFC)
3900 = 19-19-19-40 (CAS-RCD-RP-RAS), 47 (FAW), 17 (CWL), 683 (RFC)
4000 = 20-19-19-41 (CAS-RCD-RP-RAS), 48 (FAW), 18 (CWL), 700 (RFC)
4100 = 20-21-21-45 (CAS-RCD-RP-RAS), 50 (FAW), 18 (CWL), 724 (RFC)
4133 = 21-21-21-45 (CAS-RCD-RP-RAS), 50 (FAW), 19 (CWL), 725 (RFC)
4200 = 21-25-25-45 (CAS-RCD-RP-RAS), 51 (FAW), 19 (CWL), 736 (RFC)
4266 = 21-26-26-46 (CAS-RCD-RP-RAS), 52 (FAW), 19 (CWL), 748 (RFC)
 
Set VDIMM to 1.45 V to make sure your RAM is getting enough voltage, you can try decreasing it later once the board has booted ok at each RAM speed increase.
 
Once you have found the maximum frequency of your RAM you can start to try to lower the timings one at a time starting with CAS latency.
 
WARNING: Be careful when lowering RAM timings as you can corrupt the BIOS, it is a good idea to run a memory testing program like Karhu RAM test to see if your RAM is continuously producing errors. 
 
The above number are from testing 3 different RAM kits on this motherboard, 2 x 8GB Kingston Hyper-X Fury DDR4-2400 (garbage RAM, unknown IC), 4 x 8GB Patriot Viper Steel DDR4-4133 (Samsung B-die), 4 x 8GB Patriot Viper Steel DDR4-4400 (Samsung B-die).

Hi cotter32, I just noticed you posted just before my first post, so I missed it.
It looks like you have made some great progress and are seeing some nice results!
 
You make a very good point about also potentially corrupting Windows and making use of the buiit-in Memory diagnostic tool.
I found the Windows Mem tool to be frustrating for the exact reasons you mention (i.e. takes a long time, have to watch it to see the result or chase it up once it's buried in the event viewer).
I've found Karhu RAM test to be much more efficient, I have 32GB and can test ~26GB of it while running Windows - although it does not test all of the RAM, it is extremely quick to find errors.
I know it's not free but it is very reasonably priced IMO for the amount of time it has saved me.
 
You make a valid point about combining tRCD & tRP as they have been inseparable since Skylake.
I have pushed my motherboard to its limits with 4 DIMMs at 4133 MHz @ 1.31 V, 19-19-39, FAW 26, RFC 726 (can be lowered to ~540 with 1.50 V VDIMM but not really worth it IMO),
VCCIO 1.25, VCCSA 1.26 V.
 
I have found ASRock Timing Configurator 4.0.4 to be very useful for checking RTLs at high clock speed and use AIDA64's multi-threaded Cache and Memory Benchmark to confirm any gains.

 
I did the CPU overclock plus the 4000 Mhz RAM overclock .  Worked great .  Once again I let the board do most of the work .
Set CPU multiplier to 48 for 4.8Ghz all cores @ 1.203V, set RAM speed to 4000 @ 1.41V .  Got stable overclock under heavy load,
and my best Time Spy score yet:
OA          14723
Graph      16785
CPU         8681
Frame rate 98.2% stable on Time Spy stress test .  No CPU temps. over 77C, mostly runs at 58C under load .
Using Noctua NHU-9S air cooler .  Probably nearing its limit for heat dissipation .
Re Bar on, Fast boot off, Intel speed stepping on, Intel turbo boost on .
 
To the Moon ... at higher frequencies !
 
        Intel 8086K CPU + EVGA Z370 ClassK MB + 32Gig Gskill Trident Z 3200 cl 14-14-14-34 RAM + EVGA 850 P2 Plat. PSU
 

I've read of people complaining that they loaded the same settings manually that AUTO used, and got failures to POST .
I figure that they didn't use the right sub-timings, so I'm giving them all .
Somebody with experience, like yourself, might be able to make heads or tails of them :)
 
basic timing:
tCL 18
tRCD/tRP 18
tRAS 38
tRRD_S 7
tRRD_L 9
tRTP 12
tFAW 35
tCWL 18
tCMD 2N
 
second timing:
tWR 24
tRFC 522
tREFI 15600
tWTR_S 11
tWTR_L 17
tCKE 9
 
third timing:
tRDRD_SG 7
tRDRD_DG 4
tRDRD_DR 6
tRDRD_DD 7
tRDWR_SG 12
tRDWR_DG 12
tRDWR_DR 12
tRDWR_DD 12
tWRRD_SG 42
tWRRD_DG 36
tWRRD_DR 10
tWRRD_DD 10
tWRWR_SG 7
tWRWR_DG 4
tWRWR_DR 10
tWRWR_DD 10
tXP 8
tXPDLL 32
Memory SPD Write DISABLED
Voltage 1.41 .  Speed 4000Mhz
 
... of course they probably won't work for a system with different equipment :(
I have an EVGA RTX3080 ULTRA air cooled model .  My main motivation for doing this was to see if the Z370 ClassK could
make full use of the 3080 .  I'd say so far, yes it can .
 
P.S. ReBar doesn't help very much, so you're not missing much .
 
To the Moon !
 

Yes, sir, chinobino, getting good performance .  It plays smooth and nice .  The 3080 runs at 99 to 100% GPU usage during benchmarks .
I lowered the RAM voltage to 1.405V, lost a tiny bit of performance, but I'm trying not to over-volt .  Primary timings remain the same, 18-18-18-38 .
Heat will keep me from going farther .  RAM might have already gotten too hot, but I removed the plastic adornments, and have a case fan blowing
fresh air on them about half an inch away .  It's not good on my board though with the four RAM modules packed in closely beside each other .
Not much air space at all .  Also need a bigger CPU cooler .  Eventually the 3080 will find its way onto a newer mother board .  Maybe a Z690 :)
 
P.S. I knew the 8086K could do it because it has an Intel XMP profile for 4700Mhz !
 
To the Moon !
 
 

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