Hey everyone,

I recently built a new PC (11/2025) and I noticed something strange with my side fans in the case lately.

Specs

• Case: Montech KING 95 Pro
• AIO: Montech Hyper Flow ARGB 360
• Motherboard: GIGABYTE B850 AORUS ELITE WIFI7 ICE
• CPU: AMD Ryzen 7 7800X3D
• GPU: XFX Radeon RX 9070 XT Mercury RGB

Problem

The 2 side fans sometimes start a few seconds later than the rest of the fans.. but ONLY after the PC has been off for a long time (cold boot).

Important:

• The fans always eventually start (3 seconds delay)
• After they start, they work perfectly normal
• Temps are completely fine
• No fan errors in BIOS
• Restarting the PC does NOT reproduce the issue
• If I shut down the PC and immediately turn it back on, everything starts normally
• It only happens after the PC sat powered off for a while

Things I already tried

• Disabled Fan Stop in BIOS
• Set all SYS_FAN headers to PWM mode
• Increased minimum PWM from 25% to 40%
• Adjusted fan curves manually in Smart Fan 6
• Tested multiple SYS_FAN headers
• Checked temperatures
• Verified all fans spin normally after startup

The case fans are probably connected through the Montech fan hub.

Additional detail

One AIO fan also makes a very slight noise sometimes, but nothing major. Not sure if related.

At this point I’m wondering:

• Is this just normal fan hub / cold boot behavior?
• Could the fan hub be initializing slowly?
• Or is one of the fans possibly starting to fail?

Would appreciate any ideas or similar experiences.