On my PCs, I use an inexpensive non-contact thermal measuring device, designed for homeowners to use ~$20-$30
Like this one - though mine is a different brand, think I bought it at Lowes a few years ago
https://www.amazon.com/General-Tools-IRT206-Thermometer-Mid-Range/dp/B0016838JU The non-contact thermal gun needs to be held close to the item as the target area grows quickly with distance
The chipset coolers either have active cooling from the Mfg or rely on the fans in your case to move air over & around them to keep them cooler
You might also consider buying a "
Kill A Watt" type measuring device to measure the Amps your PC draws while you tune your OC settings