More likely you ran Windows8 on hardware that's not compatible. Did you do the compatibility test before installing? Win8 is dead stable.
Depends on what you call stable. I have run into several things that are either broken or Microsoft decided to remove the functionality from what was in Windows 7.
Example, Windows 8 does not remember what Control Panel setting you chose to view in, like all previous versions of Windows did. Bug, or removed functionality? Either way, it is idiotic that such things would happen.
I have had a lot of problems installing drivers, for recent hardware. Having to do it the old fashion way by manually unpacking cab files and having Windows 8 search the drive so the drivers could be installed. These are compatibility problems with the binaries packaged by the manufacturer. They work fine with Windows XP or Windows 7.
If your hardware is less than a year old, then you may not run into these driver issues. Basically, look for explicit Windows 8 driver support from the manufacturer, because even though Windows 7 drivers are used for most things in Windows 8, the installers will not run unless they are specifically made for Windows 8 for many pieces of hardware.
Intel gave up trying to produce installers for Windows 8. They just package a self-extracting zip file with instructions on how to install the motherboard drivers manually. If it is not built into Windows 8 (none of the LGA775 motherboard chipset drivers are), you will need to do it manually. While Windows 7 would run stable without the motherboard drivers, failure to install those drivers in Windows 8 will result in a very unstable system.