Unable to start VM with more than 1388MB of memory in Hyper-V

I have a question regarding Hyper-V on Windows Server 2008 R2 (Standard).

After installing and configuring Hyper-V via adding a role in the server manager, i am able to start VM only if they have less than 1388 MB of memory configured. (figuring this value out required a bit of trial and error).

When clicking the start button i have a very vague error stating the the vm failed to start. Message which is also found in the Hyper-V logs in Server Manager along with a more informative one.

The description cannot be found but it's a 3030 error, after searching up a bit i found out that it's related to insufficient ressources either CPU or Memory.

The folloqing info are included in the error:

ERA
A8055AFA-9EAB-4B6D-BFF6-3B271E7EE48D
1408
%%2147943850
0x800705AA

ERA is the VM name, the UUID on the second line is the internal UUID of the VM assigned by Hyper-V (same can be found in the config dir of Hyper-V containing the config of that VM). On the third line is configured memory and on the 4th and 5th i don't know.

NUMA is enabled as it is by default and i have more than enough free memory to start that VM:

As far as i can tell (but i may be wrong), cache memory is supposed to be cached data to prevent I/Os and can be easily freed should any process need it. I then consider i have around 9-10G memory free.

I also noticed that this value (1388) roughly comes around 2G of real in use memory (VM memory + Hyper-V overhead). It looks a bit like a 32 bits process memory size limit except that it makes no sense. Windows is 64 bits (it's a R2) and Hyper-V also (as far as i can tell there is no 32bit version of Hyper-V).

I also had a look at the CPU settings and virtualisation stuffs are enabled (Intel Vt,...)

Thanks for your help,

EDIT: I didn't disable the pagefile it's set to 1,5 time the size of the ram and stored on another volume that C:

EDIT2: I just found out that it might not only be related to Hyper-V since other processes seems to have issues assigning more that amount of RAM. (VMware Workstation and Virtualbox all have the same issue, only they allow the machine to boot until they crash when the vm actually asks for that memory).