Can YOU read! Did you even bother to look at the links!
Crucial compatible memory has been
tested for compatibility. So if it says it is compatible, then it is compatible.
Also
Kingston memory has also been
tested for compatibility. Their test includes compatible 4 GB memory.
Most memory manufacturers list TESTED compatible memory on their websites. They DON'T list what they THINK is compatible memory, they actually TEST their modules.
And from MSI website (as mentioned before), this
list is of compatible memory as tested by MSI themselves!
At the bottom of the list are two entries for 4 GB modules which have been tested and verified for compatibility by MSI themselves.
The first 4 GB entry is for part number
KVR1066D3N7/4G. If you do a Google search for that part number, you find find that it is a single 4 GB module (from Kingston; and from their Value RAM series).
The second 4 GB entry is for part number
M378B5273BH1-CF8. A Google search reveals that it is also a single 4 GB module (from Samsung).
Therefore the G41M-P26 motherboard supports 4 GB memory modules; no doubt!