How can I scan my lan for mac addresses for all the pc's in it? Tried finding a switch for Nmap but no luck so far.

Edit: nevermind, found it: nmap -sP 192.168.0.0/24

Well, on Windows you can use RivaTuner, Everest or perhaps even PC Wizard. As for Linux, I'm not sure. I have read up on GEM (graphical execution manager) which should basically be a memory manager for the GPU's ram, but I don't know how to use it. Depending on your gpu card type you can use the drivers to get the info needed(Nvidia has a nice Linux binary driver). Will try to Google how to get the info I need, if anyone knows I'm all ears.

I wonder, how much does the X server and both Gnome and KDE stress out and use the gpu(ram and processing power)?
Can anyone compare it to Aero from Win7?
I was thinking that ideally, everything shiny that is included in the DE should be in the gpu's ram. Lets say I have VLC running with the Gnome gui - are all the icons and things that the gui uses in gpu ram and animating buttons etc does not use the cpu at all or does the cpu do it?
Ideally, a program on Linux should run and react as fast as if you typed it in the terminal without gui and shouldn't take more ram when running with a gui or without it.

Thanks for the breathtaking reply, this is exactly what I was looking for!

Interesting. So basically when Nautilus or Dolphin go to a directory, they create a hash of each file and look into the .thumbnails directory if it contains the said hash. If it does they show the thumbnails of the file (or don't if it's in the no thumbnails directory), if not they will generate both the hash and a small picture as a thumbnail and put it in the .thumbnails directory.

But I still don't get why Dolphin creates a .directory file. If it's not for thumbnails then for what?

I realised that Doplhin creates a .directory file, I'm just surprised that Nautilus does not create any file. Was wondering how does Nautilus know which thumbnails are created and which aren't and how does it know the preference for each directory (where and how does it store it's thumbnail setting database).

Well for one I thought that KDE will save a single hidden file to every directory that has thumbnails, as compared to Gnome that has a global .thumbnails directory that stores all the thumbnail files.

I'd personally like the Gnome approach better as when you need to delete the thumbnail files you can just delete one directory an you're done. I also wonder ,if KDE creates only .directory files does it recreate thumbnails every time I enter a directory or does it have a similar global directory like Gnome?

I recently noticed that KDE creates a .diretory file to probably store info about thumbnails and other stuff and Gnome does store thumbnails in a centralised directory.

Can anyone elaborate this difference in more detail and compare the benefits and drawbacks of each approach?