The problem is getting annoying, because my solution only helped once. After restarting my PC, it is the same as it was before...
Originally posted by kacsa1st
hi!
now the openGL uses your CPU instead of the GPU. i bet in your old PC the GPU is kinda shit that's why it couldn't handle things well.
in the task manager you can compare these openGL settings how much load each put on your sources if u'd like.
just to see how the differences between the 2 settings in % on CPU and GPU.
aurora tends to put a ton of load on CPUs (that's why tons of ppl experiencing lag with weak PCs) but we can share the load on GPU with the openGLsetting 4.
in your case i bet the streaming with OBS puts a lot of load on your GPU and it can not handle both at the same time (PS+streaming). just my guess cos i've never streamed hence didn't use OBS 
GL at the tables and with the streaming!
edit:
i still use the old engine on ps.eu. the trick is never update untill it is inevitable (the reason is don't fix if it ain't broken).
to do this u should change the PS icon path to point on pokerstas.exe instead of pokerstarsautoupdate.exe.
with this you can avoid having no HUD after an update (which had happened several times back in the days especially on zoom tables and had to wait till the tracker creator guys updated their software too to work again)
when sg really important/big update comes it will warn you and will run the update so no need to worry using this method
You are right, my notebook is old as hell. However at least it has a dedicated GPU.
Also I don't think the heavy load of streaming is my problem. I tried to just open OBS and PokerStars and the issue is the same without even starting the stream. The preview of the stream is only the first frame of the table and doesn't refresh.

It is far from maximum load the PC can handle.
OBS works perfectly with other poker rooms (888, Unibet), that's why I thought the problem is with PokerStars settings/latest version. As far as I know, it isn't allowed to stream Unibet action, and TBH PokerStars will be my main room anyway, because I have good rakeback ATM. So if I have to choose between streaming and PokerStars, I choose PokerStars.
I bet it would be easier to solve the problem with Windows 10 installed (I use Windows 7, because I didn't find proper drivers to Win 10 and I hated to use the notebook without multitouch gestures).
I guess I can't just install PokerStars previous version now, if I updated once.
Egyébként meg köszi a segítséget!