Is this GPU real?
The used pro-GPU market is full of relabeled cards, China-flashed BIOSes, dead “for parts” units sold as working, and outright counterfeits — especially A4000s, A6000s, A100s, and H100s. Here's how to check before you wire money.
The universal 7-point check
Works for any card. Do all seven before buying used.
- 1Run GPU-Z / nvidia-smi before you pay (or the moment it arrives)
The device name, reported VRAM size, and bus must match the card you're buying. A relabeled card gives itself away here instantly. Screenshot it — eBay/PayPal disputes hinge on this evidence.
- 2Check the VBIOS version
Workstation cards have a known VBIOS version family. A wildly different prefix usually means a China-flashed or cross-flashed BIOS (often from a mining/server farm). We list the confirmed prefixes we have per card below.
- 3Match the cooler to the real product
This is the #1 visual tell. A-series workstation cards are single- or dual-slot BLOWERS with a rear exhaust — never open-air axial fans. Datacenter cards (L40, A100, H100) are PASSIVE with no fans at all. An 'A6000' with gamer-style axial fans is not an A6000.
- 4Verify the power connector
The RTX A6000 uses a CPU/EPS-style 8-pin, not a standard PCIe 8-pin. Ada workstation cards use 12VHPWR. A wrong or adapter-hacked connector is a red flag.
- 5Sanity-check the price against eBay sold-listings
If it's dramatically below the going sold-listing rate, assume it's a scam, a fake, or a dead 'for parts' card until proven otherwise. This is doubly true for H100/A100.
- 6Inspect serial stickers and MPN
Genuine NVIDIA cards carry a serial sticker and a part number (MPN) in a known format. Missing, peeling, or mismatched stickers are suspicious. We list known MPN patterns per card below.
- 7Beware SXM modules sold as PCIe cards
A100/H100 come in PCIe and SXM form factors. An SXM module does NOT drop into a PCIe slot — if a listing blurs this, walk away.
Per-card authenticity checklists
Jump to a card: RTX A4000 · RTX A4500 · RTX A5000 · RTX A6000 · RTX 4000 Ada · RTX 4500 Ada · RTX 5000 Ada · RTX 6000 Ada · L40 · L40S · A100 · H100 · GeForce RTX 4090 · GeForce RTX 5090 · GeForce RTX 3090
Workstation
NVIDIA RTX A4000
See prices →- ✗Axial (open-air) fans instead of a single-slot blower — that is NOT a real A4000 cooler.
- ✗VBIOS version NOT starting 94.04 — common on China-flashed mining/server pulls.
- ✗Missing or relabeled NVIDIA serial sticker; mismatched MPN.
- ✗GPU-Z reports a non-A4000 device ID or wrong memory size.
NVIDIA RTX A4500
See prices →- ✗Open-air axial-fan cooler — A4500 ships as a blower.
- ✗Claimed VRAM other than 20GB.
- ✗No NVLink fingerstock when listing claims NVLink support.
NVIDIA RTX A5000
See prices →- ✗Axial open-air fans — the A5000 is a blower card.
- ✗VBIOS version NOT starting 94.02 — possible re-flashed/mining pull.
- ✗Reported memory != 24GB in GPU-Z.
NVIDIA RTX A6000
See prices →- ✗A40 (passive datacenter card) relabeled as an A6000 — check for active blower.
- ✗Wrong power connector: real A6000 uses a CPU/EPS 8-pin, not a standard PCIe 8-pin.
- ✗Reported memory != 48GB; missing ECC.
NVIDIA RTX 4000 Ada
See prices →- ✗Open-air fan cooler — the 4000 Ada is single-slot blower.
- ✗Confused with the older A4000 (16GB) — Ada is 20GB.
- ✗Mislabeled 'RTX 4000 SFF Ada' (a different, lower-power card).
NVIDIA RTX 4500 Ada
See prices →- ✗Open-air axial cooler instead of blower.
- ✗Adapter-less PCIe-8pin wiring when the card uses 12VHPWR.
NVIDIA RTX 5000 Ada
See prices →- ✗Reported memory != 32GB.
- ✗Open-air cooler instead of blower.
NVIDIA RTX 6000 Ada
See prices →- ✗L40 (passive datacenter, same GPU die) sold as an RTX 6000 Ada — check for active blower + display outputs.
- ✗Reported memory != 48GB; missing ECC.
- ✗Implausibly low price for a 48GB Ada card.
Datacenter
NVIDIA L40
See prices →- ✗Sold for desktop use without warning it is PASSIVE — it will thermal-throttle/shut down in a normal tower.
- ✗Reported memory != 48GB.
NVIDIA L40S
See prices →- ✗L40 (non-S) relabeled as L40S — verify the exact silkscreen/part number.
- ✗Desktop listing ignoring that it is passive.
NVIDIA A100
See prices →- ✗40GB card relabeled as 80GB — verify reported HBM size in nvidia-smi.
- ✗SXM4 module sold as if it drops into a PCIe slot — it does NOT.
- ✗No ECC / wrong device ID under nvidia-smi.
NVIDIA H100
See prices →- ✗A100 (or lesser card) relabeled as H100 — confirm Hopper + HBM3 in nvidia-smi.
- ✗SXM5 module advertised as PCIe-compatible.
- ✗Price 'too good' for an H100 — near-universally a scam on consumer marketplaces.
Consumer crossover
NVIDIA GeForce RTX 4090
See prices →- ✗Melted/discolored 12VHPWR connector (a real 4090 failure mode — inspect closely).
- ✗Relabeled 4080 or repaired mining card — verify die + memory in GPU-Z.
- ✗'4090' with the wrong VRAM (not 24GB).
NVIDIA GeForce RTX 5090
See prices →- ✗Reported memory != 32GB.
- ✗12V-2x6 connector damage from high power draw.
- ✗Counterfeit boxes/serials at launch-window prices.
NVIDIA GeForce RTX 3090
See prices →- ✗Ex-mining card with worn fans/thermal pads sold as 'lightly used'.
- ✗3080 (10GB) shroud reused on a relabeled card — confirm 24GB in GPU-Z.
- ✗Sagging/repaired PCB, reflowed memory.
Spotted a scam pattern or have a confirmed VBIOS prefix to add? This guide grows from real buyer reports — that's the moat. (A community report form is on the roadmap.)