The fans in the clone DM800s are rubbish and will become noisy and easily clogged with fluff and dust.
I have looked at a few lately and removed the original fan on the heat sink. I then cut the cable with the fan connector just below the heat shrink sleeving which covers the resistor which is used to drop the voltage.
As the DM800 gets so warm inside it is not practical to use an internal hard drive and if you do it will soon fail with heat.
So I used the hard drive tray for mounting some larger fans which I removed from a HDD cooler.
I cut the metal on the end that went across the hdd tray which you need to do to stop the fan blades fouling on the metal and it also means you can just squash the 2 ends together so the holes on fan will line up.
I found for a single fan a 33 ohm resistor soldered in line on the power connector will make the fan run almost silent.
Below is one modified using both fans and a 15 ohm resistor for dropping the voltage which makes the fans run faster . This is mine and I am not bothered by the fan noise.
It runs very cool.
