I don't have one, but . .
I've obviously no idea of your case set up, but you need a good airflow throughout the case - sometimes the air flow can become 'disrupted' by untidy cables, extra large GFX cards etc.
The weather we're experiencing this week will also mean the ambient air temperature will be warmer than 'normal' which won't help with cooling
Check your front/rear/side/top case fans are working, and in the right direction.
Apart from that, too much thermal paste can cause poor temperature management too, although I presume you know that anyway