According to AMD Specs on the 7600X your 90c-93c under stress is within it normal Maximum Operating temperature of 95c but very close to overheating in general.
The default TDP rating for your processor is 105 Watts so your AIO should be strong enough to keep it from overheating which it is doing barely but only under stress conditions.
There are many reasons for a CPU to run hotter than normal:
1- poor air circulation inside your PC. To check that remove the side panel of your PC case and see if the CPU generally run slightly cooler with it off. If it does that indicates poor air circulation inside your PC case. Make sure all PC case fans are running and working properly.
2- The CPU Cooler was not installed properly or setup properly. Make sure the Water block is on tight and evenly on top of the processor and that the pump is working at maximum when it is getting hot and the Radiator's fans are also working at maximum when the processor is getting hot.
From Thermaltake concerning your AIO model: https://www.thermaltake.com/water-3-0-360-argb-sync.html
Cautions
Thermaltake recommends the following steps to be taken before using the Pacific series radiators and water blocks
- To ensure a clean loop, flush and rinse your radiators and water blocks with distilled water prior to use.
- Do not use tap water or distilled water as your coolant, it may harm your loop and reduce performance.
- It is strongly recommended to use market proven pre-mix coolant, such as Thermaltake Coolant 1000. It offers great performance while protecting the entire liquid loop from corrosion.
- Before storing your water cooling components, please clean, rinse and dry. This will ensure a longer lifespan for your components.
Thermaltake recommends the following steps to be taken after completing your water loop setup
- It is strongly recommended to use market proven pre-mix coolant, such as Thermaltake Coolant 1000. It offers great performance while preventing the entire cooling system – copper, brass, nickel, aluminum, and steel – from corrosion.
- Fill the reservoir with coolant and cycle the power on and off several times while the pump pushing the coolant into the loop.
- DO NOT let the pump run dry, when there is no liquid entering the pump turn off your power immediately
- Fill the reservoir to the top as it will prevent air from going into the pump
- If necessary tilt the system slightly from side to side to bleed the air out of the loop.
- Place some paper towels under fittings and joining points to test for leaks.
- Run the loop with the fill port open for about 24 hours to completely bleed the air out of the loop.
- Before starting, flush out your system correctly to prevent any coolant or unwanted particles sticking to your tubes, radiators and other cooling components.
- Coolant might fade over time.
3- Defective CPU Cooler
4- Overclocking CPU putting extra strain on AIO
5-Hot room ambient temperature. Any room temperature above 82f will make your PC run hotter than if room temperature was around 80F or below.
6- Positions of your CPU Cooler Radiators inside your PC and GPU card hot air output position.
There are probably more but those are the ones that comes to my mind at the moment.
