I have a GTX 760, AMD Ryzen 5 1500x Quad and 8gb DDR4 RAM
 
Had this computer for over a year now and the whole time the graphics card has been behaved this way. I've tried looking this up and haven't came across much about this problem other than other brands of graphics cards and what looks like different problems. Didn't think to post on the forums here
 
What's happening is as soon as the graphics card fan starts after booting the PC, it will quickly whirr up to full speed for around 10 seconds before slowing down to nothing for maybe 15 seconds. Then it will repeat this over and over. This behaviour is more or less the same when idle vs actually playing games so I have got to the point where its less annoying to run it at 90% speed all the time; when i do this the fan will not slow down to nothing but stay at audibly the same speed. 
 
I'm using afterburner and have played with the settings, reinstalled and tried everything within my knowledge to fix this.
 
If anyone has had a similar experience or can help me with this, I'd appreciate any advice
 
Thanks very much
 
James

You say that your using AB
 
adjust Hysteresis to a value of say 5  (value of 0 is the default)
 
This is the Value in C that the Temp must go below before the fan would slow
 
example: 
fan @30% & GPU @40C
fan @60% & GPU @ 60C
 
if Hysteresis is set to Zero & temp is bouncing between 59 C & 61 C --> the fan would hunt between 30% & 60% constantly
 
temp goes up to 60C, then fan increases, temp drops below 60C, fan slows ...... (repeat)
 
if Hysteresis is set to 5
 
temp goes up to 60C, then fan increases, temp drops below 55C, fan slows ...... temp stays at say 58C - fan stays at fixed RPM