I5 3450 not going into turbo mode, Any suggestions?

[CKVS]

Hello guys, i got i5 3450 a couple of years back and its working absolutely fine until i started using Flight simulator x. My rig is i5 3450 , GTX960 , 8gb 1600mhz ram, H61m-p20 Mobo from msi. I noticed while flying processor is stuck at 3.294ghz and not at all going near 3.5ghz (yes turboboost is on). I'm using stock cooler. and temperatures are 62,71,65,66 at max (check attached image). what could be the reason? high temperatures? or because of low cost motherboard? Please help

[AP16]

Flight simulator X is a multi-threaded app, with all cores under significant load turboboost is not available or very limited in range.

[CKVS]

I agree but even when i'm running prime on 1 core and all others are at idle clock is not going above 3.29ghz

[AP16]

Tcase for CPU is exactly 67.4°C, and we see some cores gets about or over that value. So can you provide data from MB sensors, like via HWMonitor tool?

[CKVS]

Here you go

[AP16]

Well, you have an ambient temp around CPU over 40C and mb sensor under cpu show us 68C - near throttling temp. There may be need of thermointerface change or general reform of system cooling - like replacing stock cooler and installing additional/better case fans.

[CKVS]

Will comply and let you know