How to minimize xorg gpu usage on ubuntu mate 18.04 laptop

I have a xiaomi air laptop with a very small gpu (MX150) and ubuntu mate 18.04 installed. I see that xorg uses up quite a bit of GPU (relative to what I have), around 185Mib on average.

+-----------------------------------------------------------------------------+
| Processes:                                                       GPU Memory |
|  GPU       PID   Type   Process name                             Usage      |
|=============================================================================|
|    0       916      G   /usr/lib/xorg/Xorg                           185MiB |
|    0      2495      G   fcitx-qimpanel                                 7Mi  |
+-----------------------------------------------------------------------------+

Also any way to mitigate the fctix process ? Am I right to think that this xorg uses gpu to render whatever theme I have installed? If so, how can I know which themes or mate features needs a lot? I am keen to minize this as I want to run ML models in there (No I don't have the money to buy gpu or use cloud).