Question Strange Gpu Heat Issue

[Lev1n]

Recenly i build a computer for myself.

Cpu : intel i5 9600k
Mobo : Msi z390 Tomahawk
GPU : GTX 780 Direct II CU OC
RAM : 8x2 Gskill Ripjaws 3200 CL 16
PSU : Xigmatek 80 Plus Gold 650 W.

My problem is i build this computer w.o a pc case. Everything is fine cpu is at 4.9 ghz at prime95 with 70-75 degree. Gpu is at 55-60 degrees at stress tests(default clocks, default fan speed)
Recently i got a pc case i put everything in to the case. Case was msi mag forge 101m. I tested cpu on prime95 its fine at 75 degrees but when i test the gpu its hitting 100 degrees in 10 second and shutting down the pc. I put fan speeds to % 100 on msi afterburner nothing changed. I try these parts on another nzxt case its same on that too. Want to know what can cause this strange heat issue.

Sorry for my bad English.

 

[Myst_8362]

brobly your fan placement

 

[Lev1n]

brobly your fan placement

Nothing wrong with these fans.

 

[Nemesia]

Sounds like your old GPU needs a replacement of the thermal paste on it. 100C inside 10 seconds with the fan at 100% is a GPU issue.

You're not overclocking it right?

 

[Lev1n]

Sounds like your old GPU needs a replacement of the thermal paste on it. 100C inside 10 seconds with the fan at 100% is a GPU issue.

You're not overclocking it right?

Everything is default. Right now its i put everything outside of case Its have 50 degrees at furmark bench with default fan speed. Idk why its getting hot inside of case.