Problem with 4000 MHZ RAM installation.
Problem with 4000 MHZ RAM installation.
Hey, I see you're working with the new RAM kit. For your i9 9900k Asus Rog z390 Gaming PC, you'll want to set the XMP profile to match your RAM specifications. Check the manufacturer's documentation or the RAM package for the exact XMP settings. Typically, you'll enter values like 1.0 or higher depending on your RAM type and speed. If unsure, start with the default values and adjust as needed. Let me know if you need more details!
Did you purchase one unit or several? It seems Coffee Lake likely can’t handle such high memory rates unless you possess a special gold sample IMC. Intel isn’t particularly known for their IMCs these days.
It's a 2x8GB kit. Many users have tried i9 9900K and 4000MHz, but it needs particular overclocking adjustments. I'm looking into those settings.
Start with XMP but adjust to 3200 or 3600 if it boots, then attempt 4000 again; possibly need to raise VCCSA/VCCIO to around 1.15
Enable XMP in the BIOS, then lower the speed to 3600 and check if it boots. Regarding high-speed RAM, compatibility isn't always perfect. You might also experiment with adjusting SA/IO voltages, though that can be complicated. Edit: That was a great suggestion! Intel IMC hasn't changed much, though it doesn't necessarily affect performance. I use a Kingston 4000 kit for testing, and it works well with all my Intel systems from Skylake onward. Performance can vary depending on the motherboard. A small issue is that newer AMD CPUs sometimes have memory modules with timings optimized for them, which might not be ideal on Intel systems. It depends on the specific kit—module makers can target either way or leave it unspecified.
During testing, values between 1.25 and 1.30 could perform even better.