i guess its a 3 pin since it came with the case, my motherboard though has a 4 pin connector to which i can also plug in a new one. I was also planning to replace that case fan with a Pure Wings 2 one.
Many case fans are 3pin. Most motherboards are 4pin. This isn't a problem. 3pin work on 4pin no issue. But there's a catch. 4pin is pwm, it's a constant 12v. 3pin fans work on variable voltage usually 7v-12v to control speeds.
So in your bios, you need to change control of that header to auto/voltage instead of pwm
No. You already have a 3pin. Your motherboard is setup to control 4pin. Go into bios and change the fan control from pwm to auto/voltage for that header.
You just need to setup the motherboard/bios for the equipment you want to use. If you buy a pure wings2 pwm, then you'd not need to change the mobo, but if that pure wings2 is a 3pin, then you would still need to make the change.