TL;DR: Clean the dust, verify intake/exhaust, log temps under CPU-only and GPU-only loads, and check power leads. Repaste + deep clean fixes most heat/noise. Mixed-load shutdowns often point to the PSU. If errors persist, stop DIY and book diagnostics.

Symptoms → likely causes (plain-English)

Symptom	Likely cause	Quick next step
Fan roar, temps >90 °C, clocks throttling	Dust-clogged filters/heatsinks; old paste; reversed airflow	Clean filters/heatsinks; verify fan direction; repaste
Rattling/whine, no change in temps	Worn bearings or cheap fans	Replace case/GPU fans; set sane curves
Shutdowns on GPU test only	PSU rails/cables or GPU thermals/VRM	Try separate PCIe leads; log GPU temps; if repeat, bench test
Shutdowns on any load, random reboots	Ageing PSU or motherboard VRM	Bench PSU; inspect board for bulging caps; diagnostics
Instant spike to 100 °C then throttle	CPU cooler mounting or paste voids	Re-seat cooler; quality paste; even pressure

What we actually do on the bench (data-first, no guesswork)

Intake & dust/airflow map — filters, fin stacks, case pressure.
Thermal logging — idle/load curves, fan RPM, hotspot deltas.
Repaste & pad check — CPU (and GPU if needed), correct torque, fresh pads if compressions are poor.
Fan/curve tuning — quiet at idle, ramp under load, no oscillation.
PSU/GPU ruling-in — isolated CPU vs GPU stress, separate PCIe rails, bench PSU if combined loads trip.
Report — temps before/after, parts needed, and a realistic ETA.

Realistic ZAR time/cost bands (Stellenbosch)

Final quotes depend on model, parts and stock. We’ll confirm after diagnostics.

Service	Typical ZAR	Turnaround	Notes
Thermal paste & deep clean (desktop)	R650–R1 200	Same/next-day	Includes fin/mesh clean, paste, curve tune → Thermal paste & deep clean
Case/GPU fan replacement	R300–R900 labour (+ fan)	Same/next-day	Price varies by fan size/quality; GPU fans model-specific
PSU swap (like-for-like)	R450–R800 labour (+ PSU)	Same/next-day	We’ll size correctly and re-route clean separate PCIe leads
Diagnostics (power/thermals)	R350–R600	Same-day	Data-first; written plan/ETA → Diagnostics
CPU/GPU upgrade (labour)	R600–R1 200	Same/next-day	Includes paste, BIOS/driver sanity → GPU/CPU upgrade

Keep it cool (simple rules that work)

Front/bottom intake, top/rear exhaust. Try to keep intakes filtered.
Positive pressure (slightly more intake CFM) reduces dust inside.
Cable tidy to keep a clear front-to-back air channel.
Quality paste/pads and even cooler pressure beat ultra-thick paste.
Separate PCIe leads to the GPU; avoid splitters on high-draw cards.

Ready to fix it the right way?

Deep clean & repaste → Thermal paste & deep clean
Rule in/out PSU/GPU quickly → Diagnostics
Plan an upgrade path → GPU/CPU upgrade
Can’t get to us? → Remote support session

FAQs (fast answers)

Do you repaste GPUs as well as CPUs?
Yes—when temps or throttling suggest paste/pad degradation. We’ll quote pads if needed.

My fans are loud even after cleaning—replace or re-curve?
If bearings buzz or wobble, replace. Otherwise, we’ll set a smarter curve to cut idle noise.

Will a bigger case help?
Often yes: more front intake and space for top exhaust = lower noise at the same temps.

Do you service in exam week/weekends?
We offer expedited and after-hours options when available. Ask on Diagnostics.

Final word

Most gaming PC pain is dust + airflow + ageing paste. Tidy that first; if shutdowns persist under combined loads, we’ll bench the PSU/GPU and give you a clear, local plan—without risking your data.