I have a Inspiron 1520 with a CPU running at half speed. I thought the original CPU, a Core 2 Duo T5450, was failing, as it was running at 1 to 1.2 GHz and it should be 1.6 MHz. I replaced it with a T8300 2.4 GHz, which now runs at 1.2 to 1.6 GHz.
I don't see anything in the BIOS that could change it. I'm going to try and flash the BIOS (it is at the newest version).
Anything else I can check?
It started failing on startup, blanking the screen after the moving progress bar finished. I tried starting up without the AC adapter, and it works, first at full speed, than back to half speed.
Could it be a bad AC adapter?
Also, with or without being plugged into AC, the processor shows as 1.6 GHz at first, but then it drops to 400 MHz.
Guess I'll be retiring this one. If it's the motherboard, I give up. I've replaced motherboards before, but this unit is 8 years old.
After further tries, I noticed the display backlight goes out intermittently.