I have an Acer V15 Nitro VN7-592G Black Edition notebook. Just yesterday, I noticed ThrottleStop reported a temperature of 95-96 Celsius on the hottest core while converting a 4K video.
I tried to replicate the results today using Prime95, and my temperatures hover in the same region.
The notebook has two cooling fans, and condensors. They have been thoroughly cleaned using compressed air, and I run the DustDefender utility daily to keep dust from affecting cooling efficiency.
One odd quirk about this whole issue is that if I take my laptop outside in the cold Canadian winter air measuring in around -10 Celsius with wind chill, and run Prime95, the CPU still sits in the same region of 90 Celsius, but the air exiting the condensor/heatsink feels very cool, and I measured it at -5 Celsius using my thermocouple thermometer. Indoors, at a room temperature of 22 Celsius, the exhaust air measures around 27 Celsius.
For the sake of comparison, my old Sony Vaio F series with an i5-2430M would run Prime95 at 71 Celsius. I could raise the temperature by blocking the exhaust vent and hit 91 Celsius easily. Even with the CPU at 91 Celsius on the Vaio, the regions surrounding the heatsink would be very hot to the touch, and the air exiting the exhaust vent would sit in the region of 70 Celsius - nearly 43 Celsius warmer than the air exiting the Acer with the CPU at the same temperature.
What appears to be happening? Is this a defective CPU, or did Acer not apply the thermal compound to the CPU properly which would explain the cold exhaust air, or is the integrated temperature sensor not calibrated properly?
Converting 4K videos is very intensive CPU task, it is expected that the processor uses all the resources to complete this task. You will see a increase on the frequency while converting any videos. One more thing you can take into consideration is that this processor TJUCTION is 100°C, and as long as your system does not crash or freeze it should be fine. If you are concern about the status of your processor you can check the health status of your processor by running the Intel® Processor Diagnostic Tool which you can find here; https://downloadcenter.intel.com/download/19792/Intel-Processor-Diagnostic-Tool Download Intel® Processor Diagnostic Tool. This tool will help to diagnostic the status of your processor.
In regard to your thermal inquiry, I recommend getting in contact with Acer since they were the ones to decide what type of cooling solution include to their products and by this I mean they should have the right answers on what to expect on this specific scenario.