Hi everyone. 
I've bought a new Fan case(3pins connect) a problem is when i install and plug connect to my motherboard(z68) at first it's look good everything work fine. but after i had opened a HWmoniter for check a status and I found this. Problem is a Fan speed PWM are very swing like 8xx-9xx pwm then to 18xx - 20xx pwm around 1-2 sec. then go back to 8xx-9xx pwm again. and it's the same showing in BIOS monitering too.
red arrow at fan#1 and #4 is the place of new Fan case.
this is a new fans Zalman from China that I've bought.(ps. a picture from internet)
A question is this new fan can make the damage to my Motherboard? or i should throw it away better.
Thank you for everycomment and sry for my weak English.(I'm from Thailand ><; )

I've bought a new Fan case(3pins connect) a problem is when i install and plug connect to my motherboard(z68) at first it's look good everything work fine. but after i had opened a HWmoniter for check a status and I found this. Problem is a Fan speed PWM are very swing like 8xx-9xx pwm then to 18xx - 20xx pwm around 1-2 sec. then go back to 8xx-9xx pwm again. and it's the same showing in BIOS monitering too.
red arrow at fan#1 and #4 is the place of new Fan case.

this is a new fans Zalman from China that I've bought.(ps. a picture from internet)

A question is this new fan can make the damage to my Motherboard? or i should throw it away better.
Thank you for everycomment and sry for my weak English.(I'm from Thailand ><; )