Do you know which ones and how? There's lots of different types of computer fans, I would think four pin at least, 2 wires for power and 2 for vdm but still not sure.
I use the Tunze fan and I switch to the hi speed and let the Apex turn it on/off when the temperature value is reached. Fans do not bring the temp down as fast as chillers so on/off should be enough...Unless I miss some other intention of the OP.
GHL offers fan banks that can be controlled via 0-10v. You would need to modify the cable to adapt it to the Apex RJ45 1-10v interface but this would offer you full 0-10v RPM control over the fans.