I have enables S3 (STR) enabled in BIOS. I have an ATI HD 4670 graphics card, and a Gigabyte EP45C UD3R board with F5C version BIOS.
When I suspend, the PC suspends happily. Since it is STR, I am assuming I should not see anything. I would have expected at least a light blinking, but it turns off totally.
On waking up, it is on for, say, 5 seconds, no display on screen, not even POST, then it turns off. Approx 5 seconds later, it turns on again. This repeats for ever, unless I do the 5 second hard OFF. After which, if I turn it on, it does a pure boot, not a resume.
In addition, pm-suspend does nothing. Nothing at all. It does not suspend the PC, or do anything else.