Your motherboard is 945G, not bad. Change it to a dual-core one. Such as T2050, T2300, etc. Taobao sells 200-300. The CPU will be significantly improved and the overall heat dissipation will be better.

Switching to a higher CPU, such as T5*** or T7***, is not recommended. On the one hand, the performance improvement is not obvious, on the other hand, it is not supported, and the notebook is not worth such investment.