Originally Posted by lumbeechief
Yeah? And so what if I buy the Z390 board, preferably ASUS MAXIMUS XI APEX, and it turns that there is no difference at all with ram overclocking? Both boards are very much similar when it comes too the power delivery and traces from the CPU and DIMM slots. The i9 is just an i7 with 2 extra cores and 4 extra threads. Why do you think it is compatible on the Z370 in the first place? It's still coffee lake with just a few extra features, nothing drastic for the need to have a Z390 board. ASUS MAXIMUS X APEX is overkill even for i9. Don't talk like i'm limiting my system because i'm not on Z390. I already talked to a few people who upgraded their CPU too the i9 on the Z370 boards, they had very high end boards as well, yet they had better luck with their ram.
Originally Posted by lumbeechief
Well according to these sources there is no big difference between the Z370 and Z390.
What you don't understand is how highend the ASUS MAXIMUS X APEX is. It's the best motherboard one could choose for the core i9 9900K and 9700K when sticking to Z370. The APEX X has better VRMs and power delivery than a very high percentage of Z390 and Z370 boards. The APEX X has an 8+2 Phase mode and is very much sufficient for the i9 9900K. My motherboard is rated to support up too +4500 MHz. It has only 2 DIMM slots which is logical for Dual Channel memory overclocking. Every highend overlocking board has 2 DIMM per channel. Just look at the EVGA DARK.
According to your sources
"If you're using an 8th Generation Intel Processor and do plan to upgrade to the 9th Gen
Grab a Z390 motherboard. Even if you’re on a budget, value options like the MSI MAG Z390 TOMAHAWK are an excellent choice. You can enjoy better overclocking and thermals on your current processor, while being ready to equip your rig with a 9th Generation Intel processor as soon as it arrives at your doorstep."
"In short, if you are thinking of buying either the Core i7 9700K or the beastly Core i9 9900K, then definitely go with a Z390 motherboard. We’ve also made a list of the best Z390 Motherboards as well if you’re looking to buy one."
However, neither source explains what could be the reason you want a Z390 motherboard vs a Z370 for memory overclocking....
It is not the VRMs - its the different QVL list and different memory optimizations / sub-timmings that you DO NOT know neither can you fix by hand...not you...a memory engineer maybe, unless you are one. This and other BIOS optimizations targeted on the NEW CPUs.
In any case, do not complain that XMP is not working on Auto - no such thing is guarranteed for the Z370 APEX NOT made for 9900K CPUs and not with a QVL memory kit. Max supported speed is irrelevant since there is much more to RAM than frequency.
And I am fully aware of the APEX as well as the others that replied to this thread....look at system signatures before assuming things since you are on overclock.net not www.averagejoe.net
Now, at least make an effort to fine tune your memory kit before exchanging the CPU...or go for it if you are sure this is the problem. Not much else can be suggested to you at this point.
I would get a Z390 before changing the CPU though and this would be after testing how good an overclocker it is.