Yep, something is not configured right for sure.
Am looking at my light, May Be a "Faint Blink" every 25 Secs are so.
Did you use Defraggler for defragging ??
What about Windows Indexer configuration ??
What AV and what's it doing in real time ??
Are ALL Processes the SAME in ALL Machines ??
Are ALL Services the SAME in ALL Machines ??
Are ALL 50 are so Built-in Tasks configured the SAME on ALL machines ??
Browsers, Caches, Startups, Etc. on ALL machines the SAME ??
You know the routine. :) :) Machine Setup and Configuration always takes about a day. (LOL) :)
Have to go through HUNDREDS of settings in Win7 to run a Good Machine.