About swap, (mostly not used)
When you use a large database or many programs at the same time exceeding your memory it has to swap out that memory to the swap partition. Standby mode keeps your system memory and swap. Sleep mode has to keep swapped memory AND all system memory wriiten to swap. Unused memory, or made available by swapping, is used by diskbuffers.
If you NEVER use sleep mode 1x mem is enough.
If you NOT use the pae or 64bit kernel, your max is 8G.
When sure not using that much programs, even working without swap is possible.
But virtual(box) machines do use a lot of mem. For faster acces you need also some diskbuffer space.
Thank you for getting back, also thanks to the all other that answered.
Never use sleep or Hibernation.
New system :- [so far]
Zalman GS1200, Asus P9X79 PRO , Intel i7-3960X, Asus HD7970, 16GB RipjawsX DDR3, SSD 256GB Crucial M4.
Had to do a clean install with PCLinuxOS KDE 2012 , because my remaster would not install [first time it [they] has failed].