My desktop PC (home-built) resumes from suspend somewhat unreliably. I'd say that it resumes successfully about 85-90% of the time and hangs with a blank screen 5-10% of the time. As far as I can tell, the success or failure of the resume is completely random. I doubt it's a software problem because I triple boot Windows 7, Windows XP and Ubuntu and it's similar under all 3 operating systems.
If it matters, my system is overclocked, though other than the resume-from-suspend issue, it's definitely rock stable. What are some of the obvious suspects that would cause random, sporadic failures to resume from suspend?