I'm running KDE 4, with some grumblings on three different machines, and the "sleep" and "hibernate" options behave badly, in different ways on each machine. In my search for solutions, I ran across a way to suspend to RAM from the command line.
I still get a "kerneloops" message, but the keyboard and wireless don't lock up this way.
I just replaced the desktop computer I've spent so much time trying to fix lately. It was cheaper to buy a debranded, no-OS machine than to buy replacement parts that might or might not have worked. I tried to get along with the laptop as my main machine, but it was not ideal.