Even if you find a working key for OCCT Pro 4.3.1, the software phones home. Within days, the key is revoked, or the software stops working.

Tool: Run Prime95 + FurMark simultaneously
Duration: 15 minutes (watch your PSU)
Watch for: Voltage drops, system shutdowns — indicates weak power supply

That five-step process already matches or exceeds what OCCT Pro 4.3.1 could do. And it costs nothing legally.

Tool: FurMark (1080p preset) or 3DMark Time Spy demo (free)
Duration: 20–30 minutes
Watch for: Artifacts, driver crashes, hotspot temps >105°C

You don’t actually need OCCT Pro. These free tools do the same job:

| Test Type | Free Tool | Why It's Good | |-----------|-----------|----------------| | CPU | Prime95 (torture test) | Standard for overclockers | | GPU | FurMark or Unigine Heaven | Free, widely trusted | | RAM | MemTest86 | Bootable, extremely thorough | | Power | Combined: Prime95 + FurMark | Pushes PSU to limit |

These are all open source or legitimately free — no cracks needed.

OCCT 4.3.1 was released years ago. Using old versions means missing:

OCCT (OverClock Checking Tool) is one of the most respected system stability testing tools for Windows. The Pro version (including 4.3.1, though newer versions exist) adds features like:

OCCT stresses your CPU, GPU, RAM, and power supply to detect: