Using Ram faster than specified on Motherboard’s website

Feb 9, 2019
I have just built my first desktop PC, based on Asus Z370-G motherboard, Intel i5 9600k CPU, Samsung 970 Pro SSD, and one 8GB Corsair Vengeance LPX 2400MHZ ram module. On Asus’s website it says it supports memory upto 2666MHZ, but can go upto 4000MHZ if over clocked. This to me, seems quite a large jump in speed. Could I not buy a 3000MHZ ram module and then over clock that not as much to hopefully reach 4000 MHZ? I don’t think I’d attempt over clocking to such a high rate, but if I can buy a faster module in the first place and then maybe add a bit of an over clock at some point, surely this is safer than trying to go from 2666-4000Mhz? The only reason I can think faster ram isn’t specified as being supported maybe because there wasn’t such fast speeds of RAM available when this board was launched? Thanks in advance for your help


I wouldn't expect 4000MHz. Anyone would simply get lucky to run 4000MHZ even if they bought 4000MHz RAM. Speeds past 3200MHz aren't worth the extra cost and don't show much performance gains.

Don't think you will buy 2666MHz and overclock to 4000MHz. I wouldn't even expect 3000MHz to overclock to 4000MHz. Maybe 3600MHz, but not 4000MHz.

Shoot for 3000-3200MHz. That's the sweet spot for price/performance.
You have one 8GB module of 2400MHz RAM which hopefully defaulted to their rated frequency and stability. This may become an issue for you when you decide you have insufficient RAM. (not enough for AAA games)
Do not mix RAM kits due to differing Latencies during manufacture.

The i5 9600k officially supports 2666MHz and the MB supports up to 4000Mhz however this depends on your IMC (Integrated Memory Controller) as to what will play fair.

RAM modules are factory binned to match frequencies they can achieve as groups in pairs or quads.
You can sometimes gain (no guarantee however) an increase in frequency of 100-1000MHz depending on the strength of IMC and your Bios capability/skills.

Quote/: Could I not buy a 3000MHZ ram module and then over clock that not as much to hopefully reach 4000 MHZ? Endquote/.

No way would that happen!!! you may if lucky get 3200MHz

The best way to buy RAM is in kits that are listed on the MB QVL (2x8) 16GB of a frequency the MB and CPU supports (for gaming). Getting frequencies above what the CPU supports is OC RAM and usually requires Bios intervention for Primary Timings and Voltage and XMP profiles do not work with OC RAM.