64 bits clients only using 2.5gb at max

[LilithWalker]

I play at 1080p, the game runs at 120fps in most areas, dungeons around 100fps, the thing is on ssp/bt, my fps drops to 15fps sometimes.

 

My build is:

 

i5 4690k @ 4.2ghz

16/24 GB ram @ 2400mhz 

Gtx 970

 

But still on those places gets to that, and what i found is the client only uses at max 2.5gb, to other friends they say the client is using 3gb-4gb, i have a friend with the exact same build as me, and he has on bt around 15-20 more fps than me, same windows, same drivers, only bns being like this, tried other games and they work as intended, using more ram, i even tried with more ram 24gb, less ram 8gb, different ways every time, but doesn't change, did test to ram but it seems it is working fine with everything else, i don't even know if the 64 bits client is working to me, in the windows process it says x64, but is like it is a 32 bits client just using that amount of ram.