View Full Version : Evolv Tempered glass edition vs. Motherboard

Rudolf Rednose
09-11-2016, 12:42 PM
Hi there,

just about the same question as many seem to have, but my case is with a Gigabyte GA-X99-UD3 motherboard, a Noctua NH D-15 (double fan heatsink) in the Enthoo Evolv atx tempered glass edition case.

How to connect the two cpu cooler fans (4 pins twice) ....I think on the CPU_Fan header with a Y splitter cable.
Is it ok to put the hub cable on any other Fan header on the motherboard?
Will it the hub have to be sata connected aswell, or does it draw power from the motherboard?
Case manual is a bit unclear on this, just expects you to connect the hub to the CPU_Fan header, which seems strange to me. (where would you plug in the 4 pin CPU cooler cables? the hub has 3 pin sockets.)

Help much appreciated.

09-12-2016, 03:52 AM
Fan hub has to be connected to a PWM fan header with PWM control on pin-4. Most all CPU-fan headers are PWM fan headers, but many other 4-pin fan headers do not have PWM control on pin-4. The fan hub requires this pin-4 PWM control.

These PWM hubs can be used with motherboard power, but it is better to use PSU power. The reason is because most fan specifications do not list the maximum power draw when fan is starting up, and this load can be anywhere from 2.5 times rated running load to 5.5 times the running load. Most fan headers are safe up to about 1 amp load.
Fan header safe limit is 1 amp, which is 12 watts.
A fan rated at 0.083 amp when running can draw .360 amp when starting up.
0.083 A is 1 watt and 4.3 watt.
3 fans running is 3 watts, but to start them it takes 12.9 watt of power.

Here is a chart of Gentle Typhoon fans running and starting specifications.
You can see how 3 fans rated at 0.12 amp can pull over 1 amp when system is booting up.

Rudolf Rednose
09-12-2016, 12:48 PM
Thanks very much for your help.

Thought so that it is a bit much, all fans one one system fan header.

09-12-2016, 11:34 PM
2 or 3 fans rated 0.12 Amp are not a problem on a single fan header, but I don't recommend any more. While fan headers may handle more, we just don't have accurate enough data / specifications for either fans or the motherboard headers to know what is safe load levels.

I wish it was like home and commercial electrical ratings .. all based on electrical rating standards . Appliances, TV, shop tools, motors, etc. had accurate power load ratings based on the maximum they will ever draw from socket. Commercial and residential wiring and panels are rated the same way .. And both have a safety margin factored into these ratings. Computer components have no such standards.