Software sluggish after 2-3 hours of play?

It is Joker Stars and the mystery of how they cannot afford decent servers with all the billions of $$$ they print.

Not to me so far.
If you're having lag issues, you can use the PokerStars network status tools to see if it is their servers.

Click "Help" on the right-hand side
Click "Show Network Status" on the left
Click "Launch Network Status Panel"

If everything shows as "very good" it likely isn't a problem with PokerStars

If you're a computer adept, you can use tools like multiping and pingplotter to see where the problem lies.
multiping does exactly what its name implies: I pings several targets at once.
pingplotter is like a fancy tracert

Cheers,
VS

It used to happen with me.

In my case i believe it was somehow related with my HUD (Hand2Note), but this also happened with HM2. When i played hudless i could play 6-8 hours without any problem.

Interesting, does this apply to you kenthmp?
If so it might indicate a problem with Hand2Note, and their support would be interested in hearing about it.

Cheers,
VS

It was not lag, it was the software itself showing very very slow animations.
Yeah I was playing with Hand2Note.

But it was happening before when I was playing hudless also.