CPU whine

There's an issue with a Latitude e5550 that I purchased some months ago. Since I prefer complete silence I swapped out the included harddrive with a Samsung SSD. However I soon started to notice a high-pitched electrical noise coming from the CPU area.

It appears that the noise is present when the CPU is idle. Not when the laptop is in sleep, but when the processor is not loaded. I have confirmed the noise is not coming from the fan because it occurs even when the fan is off and it is coming from around the CPU area. The whine varies in volume, sometimes it is unnoticable while other times you can clearly hear it from meters away.

The BIOS is up to date. Has there been some other update that fixes this issue or should I get a replacement unit?