This page on wiki lists all the relevant chipsets. As per that it won't work for sure if you have these chipsets:
- 9xx series (no DDR3 in there)
- G3x series (no DDR3 in there)
- P31 chipset (no DDR3)
- G41 chipset (4GB DDR3 only)
Might work with these:
- G4x (but not G41!)
- B4x series
- Q4x series
As the highest amount listed is 16GB, and maximum RAM socket count is 4, which implies that it is to be used with 4GB modules to achieve that, I'd say there is a chance that it won't work, but I can't say it for sure. You have to consult the specs of the motherboard to be sure...
Also, all of the relevant chipsets can use dual channel operation, which can have a very good effect on speed. In your case, I'd opt for a 2x4GB set, if it is possible to swap it, as it is most likely supported, and also performs better.
It seems to be a G45 chipset... I can only say seems, as I was not able to properly identify the device behind the device ID. This is a chhipset that has odds that it will work with the RAM, but I can't be sure...
The spec page for Acer M3900 clearly states:
Memory1, 3, 4, Dual-channel 1066 MHz DDR3 SDRAM support:
- Up to 2 GB per memory module
- Upgrade option with four unbuffered DIMM slots
And the chipset is:
Chipset Intel® G43 Express Chipset