Frequently Asked Questions
What is a PWM Fan?A PWM fan uses Pulse Width Modulation to control the amount of power delivered to a fan by cycling (or pulsing) between +12V and 0V based on a defined duty cycle (frequency). This allows a fan to operate at is correct voltage, whilst still being able to control its speed. |
Noctua NF-A12x25 Fan |
Why use a deshroud adapter over my motherboard fan headers?
Motherboard fan headers can often be reassigned to monitor GPU temperatures, however will require an often unwanted 3rd party application to be installed to do this. The control of fans by motherboard headers often can cause overheating or other issues due to the software processing required to maintain control, and the fan curve is not directly linked to overclock or under-volt settings which would be required from a secondary application. A deshroud mod will also require 2 fan headers to be used, preventing them from being used elsewhere in the system.
What fans can be used with the deshroud adapters?
Any PWM fan with standard connectors can be used, providing they are 4-pin and 12V standard. For Deshroud a pair of 120mm fans are usually used, and popular fans include Noctua, Arctic Cooling and CoolerMaster for their airflow and quiet properties.
How can I control fan speed based on temperature?The leading software for controlling fan speed is MSI Afterburner, and we recommend this is used in conjunction with a deshroud mod over GPU Tweak II or other fan control software. This can be downloaded free here: MSI Afterburner
Why does my fan RPM reach a maximum before 100% on Afterburner?A typical low RPM fan does not perform in the same way a standard GPU fan would work, and has a much lower maximum RPM speed. The PWM output is configured based on the stock fan, however the majority of fans will achieve 100% RPM prior to the 100% duty cycle being met. To counter this you will need to adjust the maximum on your fan curve, a good starting point is 50% which is typical (1800 rpm fan). In this example the default fan curve has all points reduced by 50% to provide the stock fan curve. |
Modified Afterburner Fan Curve |
To test the maximum, manually reduce the fan % in afterburner at 5% intervals, until you see a drop in RPM. The maximum duty cycle will be the last % value there was no effect on RPM. Reduce all the markers by this value to optimised your fan curve.
Also not typically this is not necessary as the default fan curve will still likely perform much quieter than the stock fans regardless, however this adjustment does allow for finer tuning of system performance.
Where is the RPM reading taken from on my adapter?
The adapter comes as standard with 2 outputs, a P= Primary and S= Secondary*. The TACH (RPM) reading is taken from the Primary header, and both fans are synced so where fans are identical (recommended) they will both have the same RPM output.
Why is my adapter missing pins?
Asus graphics cards typically have 6 or 7pin headers, controlling 2-3 fans individually based on their location with relation to GPU or memory.
GPUconnect fan adapters function like a fan splitter from the primary fan output from the GPU. This is in order to ensure there is constancy of airflow from the fans regardless of location.
In essence, both fans outputs are synced. The TACH (RPM) is read, and only needs to be read from a single fan (P = Primary). As such, the outputs from the other fans is not used, and results in not all of the pins being populated. This is by design.
* Newer designed cables do not come with labelling due to customer request, however the primary can be identified by 4 pinouts opposed to 3 on the secondary.