I just did a massive upgrade of my rig to Windows 7 Pro 64-bit w/ AMD 8-core processor. Previously, I was using Vista Home 64-bit. After being pleasantly surprised by how painless the install process was, I've just discovered my first huge gripe with this operating system.
Under Windows Vista 64, I would set my fractal rendering program to render a fractal and then go to bed. I had the OS configured to sleep after 2 hours of inactivity, and would let Fractal Extreme render until it finished. A few times, the fractal renders could take days and I would have to leave for university, but Vista sat patiently waited until the job was done, then it would sleep/hibernate the computer two hours after the fractal was finished. When I returned home, I would wake up the computer, and I was able to view the completed fractal.
Well, enter Windows 7. I swap out the motherboard/CPU combo, add a second hard drive, and put Windows 7 on it. I happened to be working on a render that would take an estimated 37 days to complete. It was 55% before I saved it and swapped motherboards. I installed Fractal Extreme on my new Windows 7 installation and get to work. The FX-8150's stock clock is 3.6Ghz, but each and every core has been fully tested by AMD to 4.2Ghz, so I go into BIOS and change the CPU ratio. Thermal design requirements be damned!
I resume the render job at 55% and go to bed. I wake up and couldn't hear the fans running, so I went to check on it, thinking the CPU may have glitched or reset. The system was out cold, so I hit the power switch and expected the worst. Up pops my Windows 7 logon screen, almost instantly.
Turns out, Windows was configured to sleep after 30 minutes, then it entered sleep mode, despite the Fractal Extreme application burning 100% CPU cycles on all 8 cores! Stupid Windows... You're not supposed to sleep when you've got a job to do! I did a quick Google search and discovered that many people had problems with Windows 7 going to sleep, with "disable power management" as the usual solution. XP and Vista did a decent job monitoring HDD activity and CPU usage, but it seems the only thing Windows 7 checks for is mouse/keyboard input. Grrr...
I'm seriously considering setting up a dual boot scenario and booting off my old Vista installation whenever I want to render fractals, if I can't find a way to make Windows 7 behave. I accidentally booted into Vista when I first attempted to install Windows 7, and I was quite surprised that Vista didn't seem throw up any activation warnings, though the display settings were effed up due to the lack of drivers.
If anyone has some tips on how to prevent Windows 7 from "sleeping on the job" without entirely disabling power management, please let me know, thanks...