Before you go: questions to ask
- Exact models of the GPU, CPU, motherboard and power supply (brand and wattage).
- Age of the PC and of the GPU, and whether any part was replaced.
- Was it ever used for cryptocurrency mining?
- Is Windows installed and activated? Any BIOS password?
- Can you see it boot and run a game or benchmark on a monitor?
A seller who knows the parts and agrees to a demo is a good sign. A seller who will not let you see it running, or wants a deposit first, is a reason to pass.
What to bring
- A USB stick with portable tools: HWiNFO (sensors), CPU-Z and GPU-Z (identification), CrystalDiskInfo (drive health), and a stress test or benchmark such as OCCT, Cinebench or a GPU benchmark.
- A flashlight to look inside the case.
- An HDMI and a DisplayPort cable, in case the seller's cable is the wrong one.
- Your phone with your price sheet, to re-check values on the spot.
- Someone to come with you, if you can.
On site: the 15 checks
Outside and inside the case
- Physical condition: dents, cracked glass, broken front ports, missing feet.
- Inside with the flashlight: heavy dust, signs of liquid, burnt smell, loose cables, missing screws.
- Power supply label: brand, wattage and condition. An unknown, no-name unit in a high-power build is a risk you will likely pay to fix.
- GPU power connectors: no browning or melting.
Boot and identify
- Cold start: ask to start it from off. It should POST and reach Windows without restarts or warning beeps.
- BIOS: if allowed, enter it and check that the CPU, RAM amount and drives are detected, and that there is no BIOS password.
- Identify the parts: CPU-Z and GPU-Z should report the same models as the listing. If the software and the sticker disagree, walk away.
- RAM: the amount and speed match the listing, and all slots populated are detected.
- Drive health: CrystalDiskInfo shows the health status and power-on hours of each drive.
- Windows activation: Settings shows whether Windows is activated. It affects how you can resell it.
Under load
- CPU stress test for 5 to 10 minutes while watching temperatures in HWiNFO. As a rough rule, most desktop CPUs throttle somewhere around 95 to 100 °C; a midrange chip reaching that quickly in a normal room points to poor cooling.
- GPU load for 10 minutes with a demanding game or benchmark. Watch for artifacts, flickering, crashes and black screens.
- GPU temperatures and clocks: as a rough rule, a core in the high 80s °C with fans at full speed, or clocks dropping sharply after a few minutes, means cooling work is needed.
- Noise: grinding fans, clicking drives, loud coil whine.
- Ports and connectivity: test a couple of USB ports, Wi-Fi if listed, and audio if you can.
If the seller will not allow 15 to 20 minutes of testing on an expensive PC, that tells you something.
Back home: the longer tests
After you buy, before you resell, run the tests that take too long on site: a memory test such as MemTest86 (often an hour or more), a longer stress test of the CPU and GPU together, and a full scan of the drives. Do a clean Windows install so the next buyer gets a fresh system and none of the previous owner's data.
Red flags: when to walk away
- The price is far below every comparable sold listing, with a rushed story.
- The seller wants a deposit, a payment app transfer or shipping before you see the PC.
- The PC is "already running" when you arrive and the seller does not want to restart it. A cold start can reveal problems a warm PC hides.
- Parts do not match the listing or the software readings.
- The GPU looks tampered with: missing screws, seals, or an unusually light card. TechRadar has reported high-end cards being sold secondhand with the GPU chip removed.
- No proof of ownership for a high-end, nearly new PC, and the seller avoids questions. Stolen goods can be seized, and you lose the money.
Safety and payment
- Meet in a public place when possible, in daylight, and bring someone.
- Pay only once the tests are done and you are satisfied.
- Never send a deposit to a stranger to "hold" a PC.
More patterns are covered in PC flipping mistakes and scams.
Prebuilt PCs vs custom builds: extra checks
- Brand prebuilts sometimes use proprietary motherboards, power supplies or cases. That can limit upgrades and lower part-out value, so check before you plan to swap parts.
- Prebuilts with a service tag can often be looked up on the manufacturer's website for the original configuration, which helps you spot swapped parts.
- Custom builds vary much more in quality. Look closely at the power supply, the cooler mounting and the cable work; a messy build often hides other shortcuts.
- Small form factor builds run hotter by design. Compare temperatures with what is normal for that case, not with a large tower.
Turning the checklist into a negotiation
Each issue you find has a cost: a power supply to replace, fans, a bigger SSD, a Windows license, a cleaning job. Add them up and use the total to make a calm, specific offer. Then use the result to price the PC for resale.
Practice with feedback
The first few inspections are the hardest; you will not know what "normal" looks like for each part. The PC Flipping course and community on Learnea includes inspection and testing lessons, 1-on-1 coaching and a members-only community where you can share screenshots of a test before you pay. For the whole process, read how to flip PCs for profit.