Slowdowns while playing Gran Turismo 4

[Domis714]

So basically while playing GT4 for a while the speed of the game usually drops around 50-60 % every 5-10 seconds, after that the speed goes back to 105 %, that is really annoying. Tried to tinker some settings, however, no improvements on performance were made. Even with native resolution slowdowns occur. Tried to run on PCSX2 1.7.0 and latest nightly versions - didn't work. Is there any way to resolve this issue?

Specs:

Intel Core i5-9300h CPU, 2,40 GHz
8 GB ram
Nvidia Geforce GTX 1650
250 GB SSD

Pictures of settings:

[Khi]

In the Qt version, click on „Tools” and tick „Show Advanced Settings”. Then you will see the „Advanced” tab in the per-game settings with these options. If this does not work, then perhaps you have activated certain cheat codes like those weird PAL2NTSC codes or something?

Edit: This post should be moved to this thread.