Fan noise (don't know which one)

[nms71]

I just got my new pc. Have a really weird sound coming from one of the fans. The sound is something like rrrrrr rrrr rrrr (almost like a revving noise) When I am off the game and just surfing around it is quiet. I have two programs that monitor CPU/GPU and they are fine. Once I start to play world of warcraft that is when that sound starts up. I checked GPU temp and it seems like that sound always starts when it hits around 50c. I called the place I got the PC from and they were NO help. I have tried opening the case to get it to make that noise again so I could pin point what fan it could be didn't work. Is there anything else I might try to rule out what fan it is?

I want to say its the graphics card it just seems like a coincidence every time i play wow that noise starts and temp is over 50c.

card in there is
MSI GT 730 (ddr3 version)

 

[i7Baby]

Stop them one at a time for less than a second with a pencil to find which one it is.

 

[nms71]

I have read trying a pencil or pen cap. As soon as I stop playing the game and leave it idle that noise stops. I don't have anyone to help me keep the game going or try the pencil/cap 🙁

 

[i7Baby]

Then vary the speed of one fan at a time.