On my Aspire A315, I'm facing this problem since a couple of days. The CPU is stuck at 400Mhz for some reason. And the machine is barely useable.
The biggest success so far was updating Bios from 1.09 to 1.11, which caused it to run at a x16 Multiplier, 1600Mhz until the next reboot, where it is now stuck at 400 again.
- Fan-Speed control seems to be working fine. Now it starts at around 50°C at very low speed, cools the CPU down to approx 40°C and then stops again.
- BIOS update was done to latest version
- Installed latest AMD Drivers
- Installed Acer care center and updated everything
- I took out the battery and cmos battery for a while to reset everything
- Toyed around with windows power plans, CPU min power to 100% and everything with no success as well.
This happens on Battery and Plugged in alike.
Any further Ideas are very welcome.
Or should i just turn it in for repair ?