Buying Used SSDs on eBay: TBW, NAND Wear, and What to Check
Used SSDs can be great value — a used Samsung 990 Pro 4TB at 60-70% of retail is a solid deal if the NAND still has life left. But unlike hard drives, SSDs have a hard wear limit. Every flash cell can only be written a finite number of times before it fails. This guide will help you evaluate used SSDs and avoid buying someone else's worn-out flash.
For the general eBay safety basics (seller reputation, buyer protection, red flags), see our Buying Used Hard Drives on eBay Guide — everything about seller vetting and eBay buyer protection applies equally to SSDs. This article focuses on what's different about SSDs.
The Key Difference: SSDs Wear Out
Hard drives fail mechanically — bearings seize, heads crash, motors stop. SSDs fail differently: every NAND flash cell degrades a little each time it's written. After enough write cycles, the cell can't reliably hold data. This wear is measured in TBW (Terabytes Written).
TBW Quick Reference
- TBW = Terabytes Written — the total amount of data written to the drive over its lifetime
- DWPD = Drive Writes Per Day — how many times you can write the full capacity per day over the warranty period
- A 4TB SSD rated for 2,400 TBW can handle ~1.3 TB written per day for 5 years
- Most consumer workloads write 10-30 TB/year. Even a heavily used SSD rarely exceeds 100 TB/year
How to Check SSD Health
Before buying, ask the seller for a CrystalDiskInfo screenshot. For SSDs, the critical numbers are different from HDDs:
| SMART Attribute | What It Means | What to Look For |
|---|---|---|
| Total Host Writes (TBW used) | Total data written to the drive since new | Compare to the drive's TBW rating. Under 50% used = great. 50-80% = acceptable if price is right. Over 80% = avoid. |
| Percentage Used / Wear Leveling Count | How much of the NAND's endurance has been consumed | 0% = new, 100% = end of rated life. Some drives keep going past 100%, but you're on borrowed time. |
| Power-On Hours | Total time the drive has been powered on | Less important than TBW for SSDs. A drive with 30,000 hours but low TBW was mostly idle — that's fine. |
| Available Spare | Percentage of spare NAND blocks remaining | 100% = all spares available. Below 10% means the drive is running out of replacement blocks for worn cells. |
| Media Errors / Uncorrectable Errors | NAND read errors that couldn't be corrected by ECC | Should be 0. Non-zero means NAND degradation is causing data errors. Walk away. |
| Temperature Warning Count | Times the drive hit thermal throttle temperature | High count suggests the drive was poorly cooled. NVMe drives are especially prone to overheating. |
TBW Ratings by Drive Class
Not all SSDs are created equal. Enterprise and prosumer drives have dramatically more endurance than budget consumer drives:
| Drive Class | NAND Type | Typical TBW (4TB) | Used Buy Value |
|---|---|---|---|
| Enterprise (PM1733, Micron 7450) | TLC / SLC cache | 8,000 - 25,000 TBW | Excellent — massive endurance headroom |
| Prosumer (Samsung 990 Pro, WD SN850X) | TLC | 2,400 - 3,600 TBW | Good — plenty for most workloads |
| Consumer (Samsung 870 EVO, Crucial MX500) | TLC | 1,200 - 2,400 TBW | Fair — check TBW carefully |
| Budget QLC (Samsung 870 QVO, Crucial P3) | QLC | 720 - 1,440 TBW | Risky — lowest endurance, wears out fastest |
QLC SSDs: Extra Caution When Buying Used
QLC (4-bit per cell) NAND has the lowest endurance of any SSD type. A used Samsung 870 QVO 8TB is great value when new, but buying one used means you're getting NAND that's already been partially worn out — and QLC doesn't have much wear budget to spare. Always check TBW used vs rated, and avoid any QLC drive above 50% wear.
NAND Types: What Matters for Used Buyers
More bits per cell = cheaper per TB but fewer write cycles before the NAND wears out. For used SSDs, this directly affects how much life is left:
- TLC (3-bit, ~3,000 P/E cycles) — the sweet spot for used. Most modern SSDs (Samsung 990 Pro, WD SN850X, 870 EVO) use TLC. Plenty of endurance for a long second life.
- QLC (4-bit, ~1,000 P/E cycles) — lowest endurance. Budget drives like the Samsung 870 QVO. Be very cautious buying QLC used — there's less wear budget to spare.
- MLC (2-bit, ~10,000 P/E cycles) — older prosumer drives. If you find a used MLC drive with low wear, it's a great buy.
More bits per cell = cheaper per TB but less endurance. When buying used, TLC is the sweet spot — enough endurance for a long second life, widely available, good performance.
SSD-Specific Red Flags
Walk Away If You See
- No SMART data provided and seller refuses to share CrystalDiskInfo screenshot
- Percentage Used at 100% or above — the drive has exceeded its rated endurance
- Available Spare below 10% — running out of spare NAND blocks
- Media/Uncorrectable Errors above 0 — NAND is actively failing
- Firmware version is extremely old — may have known bugs or vulnerabilities
- "Data center pull" with suspiciously low TBW — SMART data may have been wiped
- Counterfeit drives — Fake Samsung SSDs exist. Check the label font, holographic sticker, and verify the serial number on Samsung's warranty checker if possible
NVMe vs SATA: What to Know When Buying Used
| Factor | NVMe (M.2 PCIe) | SATA (2.5") |
|---|---|---|
| Speed | 3,000 - 14,000 MB/s | ~550 MB/s max |
| Used pricing | Higher — still in demand | Lower — often better $/TB |
| Overheating risk | Higher — check thermal throttle count | Minimal |
| Physical damage risk | Fragile M.2 connector | Rugged 2.5" form factor |
| Compatibility | Check PCIe gen (3 vs 4 vs 5) and M.2 slot availability | Universal — any SATA port |
| Best used buy | Samsung 990 Pro 4TB, WD SN850X 4TB | Samsung 870 EVO 4TB |
NVMe Thermal History Matters
NVMe SSDs run hot, especially Gen 4 and Gen 5 drives. A used NVMe drive that was run without a heatsink in a poorly ventilated system may have spent thousands of hours thermal throttling. Check the Temperature Warning Count in SMART data. High throttle counts mean the NAND experienced repeated thermal stress, which accelerates wear.
Testing After Purchase
SSD testing is faster than HDD testing since there are no mechanical parts to stress-test. But the checks are different:
Day 1: Health Verification
- Run CrystalDiskInfo (Windows) or
smartctl -a /dev/nvmeXnY(Linux) — verify SMART data matches the listing - Check Total Host Writes and Percentage Used — compare to the drive's TBW rating
- Verify Available Spare is above 90%
- Check for Media Errors — should be 0
- Verify firmware version and check manufacturer's site for known issues
Day 2: Performance and Integrity
- Run CrystalDiskMark — sequential and random speeds should match the drive's rated specs (within 10%)
- Run a sustained write test — write large files (50+ GB) to check if the SLC cache is working correctly. Speeds should stay consistent, not drop to a crawl mid-write
- For NVMe: monitor temperature during the sustained write. If it throttles heavily, the drive may have cooling issues
- Run fio (Linux) or ATTO Disk Benchmark (Windows) for a second opinion on throughput
Day 3-5: Extended Monitoring
- Use the drive for your intended workload
- Monitor SMART data daily — Percentage Used should not jump unexpectedly
- Watch for BSOD, freezes, or disappearing drives — these can indicate failing NAND or a bad controller
- If everything is stable after 5 days, you're good
Counterfeit SSDs
Fake SSDs Are More Common Than Fake HDDs
Unlike hard drives (which are difficult to counterfeit due to mechanical precision), SSDs can be faked by putting cheap, slow NAND into a branded enclosure. Fake Samsung 870 EVOs are especially common on eBay. Signs of a counterfeit:
- Price is significantly below market (30%+ cheaper than DiskDojo listings)
- Label printing quality is poor — fuzzy text, wrong fonts, misaligned stickers
- CrystalDiskInfo shows an unknown or generic controller instead of Samsung/WD/Phison
- Performance is dramatically lower than rated specs
- Capacity shows correctly but the drive crashes or corrupts data when actually filled
- Serial number doesn't validate on the manufacturer's warranty lookup
Summary: SSD Buying Checklist
Before You Buy
- Check DiskDojo for current market price — ensure the deal is realistic
- Request CrystalDiskInfo screenshot showing SMART data
- Calculate TBW used vs rated — under 50% is ideal, over 80% is a no-go
- Check Percentage Used / Wear Leveling — lower is better
- Verify Available Spare is above 90%
- Confirm Media Errors = 0
- Know the NAND type — TLC is the sweet spot for used, be cautious with QLC
- Verify seller has 98%+ feedback and 100+ sales
- Pay through eBay only — never external payment
After It Arrives
- Run CrystalDiskInfo — verify SMART data matches the listing
- Run CrystalDiskMark — speeds should match rated specs
- Run a sustained write test (50+ GB) — check for SLC cache issues
- For NVMe: monitor temperature under load
- Watch for SMART changes over 5 days of use
- Only trust with real data after all tests pass
Used SSDs can be excellent value, especially prosumer TLC drives like the Samsung 990 Pro 4TB and WD SN850X 4TB. The key is checking TBW used — unlike HDDs where power-on hours are the main concern, SSDs have a quantifiable wear limit. Check the SMART data, verify the NAND has life left, and you'll get near-new performance at a significant discount. For hard drive buying advice, see our Buying Used Hard Drives on eBay Guide.