Hibernate/Suspend will not poweroff on desktop, breaks network, Intrepid Ibex

Binary package hint: hibernate

On Intrepid Ibex, AMD Athlon 3800 X2, M2N-Sli Deluxe, 3Gb ram/3Gb Swap...
The computer does not power off at the end of the hibernate or suspend but restarts.

Hibernate (to disk...):
If I try Hibernate, computer restarts and network is functioning. If I stop the computer manually during the pause when the lights and fans stop (before it restarts) the next time it is started it is as if the hibernation was working (all my apps are still on)

Sleep (to mem):
If I try the sleep mode, the computers enters in sleep, makes a pause (fans, lights, disks all off) then restarts. Network tries to reconnect but fails to do so. Whatever I try, i have to restart the computer to get network back

It is like that 100% of the times
I made text files with the logs just after a failed sleep. available on request.
This is bugging me a lot because I usually never stop my computer just suspend it to mem (much faster...)

dont mind the english... i'm french.