I got a used fx 9590 with a corsair 2500 rpm liquid cooler on an m5a99fx pro r2.0 mobo. When playing Rocket League the whole pc will freeze sometimes. If I underclock the cpu at 4400 mhz nothing freezes but the clock is always at 4.4ghz so it consumes a lot of power. Is the extra power that consumes really that big of a difference? Plus if everyone got a way to stop it from freezing pls tell me. (ive tried undervolting but even with the smallest undervolt the pc wont start)
Put everything back to default including your processor.
Then download and stress test your CPU, GPU, and PSU using OCCT.
See if any of the 3 tests fails. While running those 3 tests check Temperatures, PSU Outputs 3.3v/5.0v/12.0v, and Fan speeds and all other data to see if you notice anything out of the ordinary.
But everything must be back to default including your BIOS (CMOS CLEAR) plus your Processor to get a good indication of what is causing your freezing.
Could be a bad or corrupt driver like the GPU driver or possibly a hardware is overheating or is going bad. That Processor FX9590 is a high wattage processor. Good thing you have a AIO Liquid CPU Cooler installed.
Could also be defective hardware like RAM Memory or HDD/SSD.
You can run in a elevated Command Prompt DSKCHK /f/x/r to check your Windows drive. The Windows Drive will be checked for bad sectors when you boot up and before entering Windows.
You can also run Window 10 Memory Diagnostics or better yet MEMTEST86 to check your RAM for defective Memory Modules.
All of the above is to generally eliminate defective hardware or other hardware related issues.
You need to monitor temperatures closely, most likely it throttles due to overheat.