CPU not using full power and at low temps under load

[Abbijeet]

I have both a desktop and a laptop with similar specs. Desktop- i5-6500, gtx1050ti, msi h110m grenade, 8gb 2133mhz ram, corsair vs450 psu

Laptop - i5-8300H, gtx1050(4gb), 16gb 2400mhz ram 

I play games like assassins creed odyssey, watchdogs 2 etc.

My desktop cpu seems to be too weak to run odyssey at 60fps as frametimes are in the 20-25ms. But while using msi afterburner to check statistics, it is boosting to the all core 100mhz turboboost and is at 95-100% utilisation throughout. But power usage is in the 20-25W range while being a 65W TDP chip. The temps are also really low, i never saw it going above 55°C whatever the load is. 

The issue then comes to my laptop which overheats near instantly to 95-98°C on the cpu and gpu sits close to 85°C under 90%+ load. The cpu here uses 30+W quite frequently and goes to the 3.9ghz (max all core boost) dropping occasionally to 3.6-3.7 ghz range even at such dangerous temps. I have undervolted the cpu by -0.15V using Intel XTU but i feel thats not doing anything. I have also tried changing the thermal paste, using a laptop coolerpad with fans but no change ever happens.

Is there something i can do so that the cpu in the desktop performs better, and the cpu in the laptop to run a bit cooler?