FSX Freezing With PMDG Aricraft After 5-6 Hours

[tcas_test]

Ever since I started doing long hauls with FSXWX and the PMDG 777, I realised that my sim would start freezing at intervals of about 5 seconds (runs for 5 sec, pauses for 5 sec, runs for 5 sec etc.) after flying for about 5-6 hours. It may be worth mentioning that I only have the free version of FSUIPC so I don't think autosave would be the cause of this. I have also realised that if I close Vpilot (I fly on Vatsim) after the freezing starts, the sim goes back to normal but then Vpilot won't allow me to connect to FSX again which is annoying. Another (probably obvious) observation I have is that this only happens when I have internet connection. I was flying at a friend's house and I couldn't connect to his Wifi so I used my phone's hotspot to reload the FSXWX weather every 30-60 minutes so that I wouldn't be stuck with the same weather for the whole flight. No freezing ocurred. This has lead me to believe that the problem is being caused by FSXWX loading/re-injecting weather over a certain period of time. This doesn't happen on any other aircraft apart from the PMDG 737 and 777. I have no clue how to fix this issue and any help would be appreciated.

Regards

Having the exact same issue.