Sleep Issues

Ever since I got an iMac, I’ve noticed some changes in my PC.  For one, the boot sequence hangs on AHCI detection and second, the S3 sleep keeps being disrupted and the computer reboots on waking.   I wonder what is causing such disquiet in slumber and waking.  Not be outdone, my iMac seems to have difficulty finding its keyboard from time to time.  Maybe I should introduce the two and see if there’s a case of unresolved sexual tension on the network stack.