Game freezes when opening inventory

[wok 1]

I recently fixed my old computer so I can play while I work on my main pc. It's an old dualcore with a gts250 and 3gb ram. Arma 3 runs quite fine, doesn't look as pretty as in my main pc but it's totally playable. The only problem is that when opening the inventory or map or pressing esc, the game freezes for like 30 seconds.

I was wondering if there's something I could do to prevent this, like some of those launch params or something, or the computer is just too old for A3?