Quick Answer

A gaming PC that keeps rebooting almost always points to power or heat: a failing or undersized PSU, an overheating CPU/GPU hitting its shutdown limit, or unstable RAM. Start by checking temps and confirming your PSU wattage matches your GPU - an RTX 5070-class build needs at least a quality 650-750W unit (around R1,200-R2,000 locally). Random reboots under load are the PSU; reboots at idle are more often RAM or driver faults.

Power supply first

Unexpected reboots specifically during gaming load strongly suggest the PSU cannot deliver enough clean power. A modern GPU like an RTX 5080 wants an 850W 80+ Gold unit; an RTX 5070 or RX 9070 XT is happy on a quality 750W. If your PSU is old, no-name, or undersized, replace it - a reliable 750-850W unit at Evetech runs roughly R1,500-R2,500 and is cheaper than a fried component.

Heat and shutdown limits

CPUs and GPUs reboot the system to protect themselves at critical temperatures (often around 100 degrees for the CPU). If reboots come after 15-30 minutes of play, log temps with HWMonitor - anything passing 95 degrees means dust, dried paste, or poor airflow. Clean the cooler and reapply paste (around R250-R450) before suspecting anything else.

RAM, drivers, and BIOS

Reboots at idle or random crashes often trace to unstable memory - run MemTest86 overnight, and if you enabled EXPO/XMP, test with it off. A clean GPU driver install via DDU rules out driver faults, and updating the motherboard BIOS fixes stability bugs on newer AM5 and Intel boards. Work through these before buying parts.

FAQ

Why does my PC restart while gaming but not at idle?

Reboots under load almost always mean the PSU cannot supply enough power for the GPU's peak draw, or the CPU/GPU is overheating to its shutdown limit. Check PSU wattage and load temps first.

What wattage PSU do I need to stop reboots?

Match it to your GPU: 650-750W for an RTX 5070 or RX 9070 XT, 850W for an RTX 5080. A quality 80+ Gold unit at Evetech runs roughly R1,500-R2,500 and prevents power-related crashes.

Can bad RAM cause reboots?

Yes - unstable memory or an aggressive EXPO/XMP profile can crash and reboot a PC. Run MemTest86 overnight and try disabling EXPO to isolate it before replacing other parts.

TIP

with HWMonitor during a reboot-prone session - if nothing passes 95 degrees, the PSU is the prime suspect, and a quality 750-850W unit from Evetech is the fix.