It applies to many systems and cards. You can usually pull the case cover off and point a fan at the open case. If it takes longer to drop, you know what needs to be done.
Read http://www.tomshardware.com/reviews/radeon-r9-290x-thermal-paste-efficiency,3678-3.html
Bob
So I got a serious problem,
Everytime I play a game (for example GTA V) it sits around +-60FPS.
After a few minutes the first drop starts. It stays for about 5-10 seconds. Same for other games, BF4 etc.
I already uninstalled the Video Drivers + ran a program called: DDU Display Driver Uninstaller.
My GPU Temp sits around 60.C and my GPU around 40.C.
My Setup:
-Sapphire R9 280X Dual-X 3GB OC
-AMD FX-8350
-2X4GB 1333mhz DDR3 RAM
-Cooler Master Seidon 120V V2
-ASUS M5A78L-M/USB3
-Cooler Master GX750
-120GB SSD
-500GB HDD
No Overclocking was done.
Only set the SATA config to AHCI and turned AMD Cool 'n Quiet off in the BIOS.
I run the latest Drivers now: AMD 15.4BETA, latest motherboard drivers. Everything seems up to date.
Hopefully somebody knows what's going on, thanks in advance.
Greetings Kars

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic