hp tower 290 g9 i713700 upgrade options and heating issues

[oliver_kareski]

While working on the PC, using excel, browser (youtube or some graphic intensive site) or small game from 2007 that uses 300mb (spec says 2 GB - 4 GB) of system ram and vram 256 MB - 512 MB, and cpu: 2.8 GHz - 3.5 GHz.

The cpu tends to overheat, idle temperature are ranging from 45 to 56 degrees C, and after 10 - 30 minutes using the above mentioned software the cpu overheats from 89 to 99 degrees, meanwhile down clocking and crashing running programs games.

Also, games tend to freeze, but keep accepting inputs and character seem moving (seen from another computer). And when the monitor is turned off or goes in suspend due to power policies, the games or any graphical programs freeze.

I sent the PC to the local official (I am not sure about their relation, I just assume they're local partners, since the branding and things) HP partner, they told me the PC was in a good shape and working according to specification, also they told me it's not for gaming, only for office use. However modern office uses more graphic intensive programs such as photoshop, corel draw, 100 tabs in their browser and what not, which way more graphic intensive than a game from 2007 that can run on a calculator.

This game and other applications I use never crashed on the similar or older intel i3- i7 CPUs.

Because I cannot deal with the local service, can you help me upgrade the PSU, I assume that the down clocking of the CPU and increased temperatures is maybe because PSU wattage is running over capacity, that's why maybe I need to change the PSU to something like 500w.

Listing the specification I see these compatible PSU's:

POWER SUPPLY1
180 W
EPA90 (Gold) +12V
260W
EPA92 +12V
350 W
EPA90 (Gold) Power Supply
500 W
EPA90 (Gold) Full range 115V/230V

But, since I cannot obtain the parts (or don't know where find them in my country, can I use some converter (24Pto6P) for the P2 connector to use standard ATX PSU?

Also, I'd like to install x16 GPU card, from the specification says it's recommended to use:

NVIDIA GeForce RTX 4060 8GB GDDR6 GFX 
AMD Radeon RX 6300 2GB GDDR6 GFX 

What cooling sink cpu fan to use as replacement for the stock fan?

If I don't install the upgrades mainly because it's still under warranty, how to approach the local service for their misconduct and how convince them to get a refund?

I send the PC twice already, and they returned the same answer, also I gave them monitoring benchmark report for the CPU temperatures and wattage in all cases I mentioned, but they refused the evidence.

So, the PC is bought through a telecom company, that has supplier chain that distributes HP and other computers, but the service is a local HP partner or something with HP servicing.

The problem is the service has to green light that refund should be issued and the supplier will get that note and tell the shop process a refund, and I am trapped on their mercy, but meanwhile I am losing time in my business not having a PC, for 6 months.