FOSS gamedev and creative worlds

Hello,
I' ve got a Minetest version 0.4.2-rc1 (engine) and game with mods:
* mesecons
* ambience
* animals (1.3.0)
* animatedtorches
* beds
* bobblocks
* bones
* building_blocks
* carts
* drippingwater
* growing_grass
* lavacooling
* nether (+ obsidian)
* madblocks
* moreblocks
* moreores
* nature
* oil
* panes
* particles
* steel
* worldtime
* xfences
and Realistic Texture Pack.
I run it on my netbook with dual-core AMD E-350 Processor and Radeon 6310 (and the GPU + CPU builds an APU).
Recently, I have noticed an issue that is present both in multiplayer game and in singleplayer game, but in multiplayer happens faster. After one in-game day and night in a new world (in singleplayer) the server seems to hang or become unresponsive, which is seen in game as mobs stopping to move, time stopping to change, inventory/crafting not working and so on. This persists on that world and to play normally I have to create a new one. Is there any solution to that problem? That is because it is really annoying and causes the game to be practically unplayable. And is the problem on the server or on the client side?
EDIT: Removed Realistic Texture Pack, works - for now...

Remove animals mod

On a netbook? i am surprized all those mods even ran for a minute...

If "realistic texture pack" means the one I make, it is not at all suitable for a netbook. It is meant for higher-end gaming rigs.

@xyz: Thanks, it really helped, although I' m missing the mobs now. At least I can play.
@rubenwardy: Yeah, on a netbook, but it' s Asus Eee PC 1215B, rather powerful one ;).
@VanessaE: No, it' s not your Realistic Texture Pack...

For now it works, it seems to be lack of resources and too many mods that caused the problem. Thank you all for help :).