So i gust got an asrock 970 de3 u3s3 mobo and also a sapphire 7870. My nzxt source 210 case had a 3 pin connector cable thing coming out of the fan, as well as a power plug. I am asuming this is the speed control because it doesn't metion anything in the manual. I was going to plug this into the chasis on my mobo, but they are covered up by the 7870. Is it ok to use the power fan as my chasis fan? thanks.
The short answer is, yes. You can use the pwr fan header for any fan. It just won't provide any speed control from BIOS. It will run the fan at +12V/full speed. Or you can connect the fan to a Molex from the PSU.