I finally decided to try changing my memory sticks. My original Corsair modules seemed to be more optimized for AMD rather than Intel.
I switched to DDR5 RAM – G.Skill – TR5CK – 48GB – 8400 MHz – CL40 – CUDIMM, which is supposedly optimized for Intel Z890 only.
I’m using an ASUS ROG STRIX Z790-F GAMING WIFI motherboard, and according to the QVL, none of the listed memory kits exceed 7200MHz. So I took a bit of a gamble with this high-end (and expensive) kit (€353).
By default, the memory has 2 XMP profiles – one at 6400MHz and another at 8400MHz.
My system won’t boot with any frequency above 8000MHz. From what I’ve read, this motherboard officially supports up to 7200MT/s.
So I ran several tests using various G.Skill XMP profiles: 7200, 7600, 7800, 8000…
7200MHz booted easily, but other frequencies gave me errors in OCCT. I used ChatGPT to help graph timings and adjust values. After 2 hours of booting and running benchmarks, I managed to stabilize at 7800MHz.
Tested RAM:
F5-7200J3646F24GX2-TZ5K
G.Skill TR5CK - 48GB (2x24GB) - 8400 MHz - CL40 - CUDIMM
Link to product on Cdiscount
You can load the 8400MHz XMP profile and then manually set the following parameters:
DDR5-7200 CL36-46-46-115 1.35V
48GB (2x24GB)
tRFC: 683
tRFC2: 791
DDR5-7600 CL38-48-48-125 1.40V
48GB (2x24GB)
tRFC: 721
tRFC2: 835
DDR5-7800 CL38-48-48-128 1.40V
48GB (2x24GB)
tRFC: 695
tRFC2: 825
Note: I had to lower the tRFC values for 7800MHz to stabilize the system. Why that worked? I honestly have no idea – but when I increased those values, benchmark errors showed up after just 10s instead of 50s. It was a trial-and-error process.
As for 8000MHz, I tried increasing timings and voltage, but nothing worked. I concluded I’m limited by the hardware.
OCCT Benchmark Results:
00:00:00 - Info - Benchmark schedule started at 2025-05-17 05:04:39
00:00:10 - Info - Memory - Read : 2,643.98
00:00:21 - Info - Memory - Write : 1,809.94
00:00:32 - Info - Memory - Combined : 2,155.07
00:00:33 - Info - Upload successful
