I have Dell G5 5587 laptop in top configuration (i7-8750H + 1060). After playing a game one day, tons of colorful dots all over the screen appeared. After a while, the system (both Windows 10 and Manjaro Linux) stopped to render image on internal display. External display, which is connected to the dGPU, works fine.
It seems like an iGPU went dead, because deinstallation of iGPU driver helps to make internal display work. Nonetheless, artifacts are still there and the system works really sluggish due to the fact that the image is rendered via CPU, not GPU. It is impossible to use the laptop this way.
My warranty went void a long ago. What can I do to get my laptop working just like before? I don't want to spend another $1000 for motherboard replacement due to a manufacturer's issue.
You should use ONLY the drivers provided by DELL.
If it is a hardware issue, the issue is between you and DELL. Regarding Dell's warranty, again that is between you and Dell. Dell is solely responsible for support of your laptop, and its warranty.