Hi there guys, I just came up with my new case build in the Jonsbo Z20:

i9 10900KF
Gigabyte RTX3070 oc v2
Asus Z490G wifi
2x16GB DDR4 3000MHz C15 Corsair Vengeance RGB
1x 512GB m2 samsung EVO placed on the MB
1x 2TB SSD samsung
(top EX) NZXT Kraken X53 paired with 2x 120mm NZXT RGB aer 2 fans PWM
(bottom IN) 2x BeQuiet! Pure Wings 3 high speed 140mm PWM

(rear IN) 1x termalight TL-9015B slim 90mm PWM

Corsair RM750e (2025)
1x NZXT USB HUB
1x NZXT RGB and fan controller (AC 2RGBC B1)

After 5 minutes of Prime95 it gets a lot hot and also fans are going crazy loud. I don't care that much about doing things 10, 20 seconds faster so I'd like to underclock the CPU in order to cool it down a bit.
It's been like 2 days since I'm trying but from the BIOS it only downclock the CACHE voltage (not the CORE), and if I try from Intel XTU it crashes (I tried 0.075, 0.070, 0.065, 0.060).

Anyone can help me?

Also: I can't install a proper 120mm fan on the rear cause the tubes are interfering, should I buy a new 240 AIO? I saw that the EK Water Blocks EK-Nucleus AIO CR240 Lux D-RGB 240 works great and it's the best for temperatures, thanks a lot!

NOTE: I already put the tubes on right instead of UP, it was a mistake during the build. The Thermal Paste used is a T9 from Termalight.

NOTE 2: room temperature: 26.3°C