How do I check whether my supplier used the memory brand and grade I specified?
You cannot verify memory brand from the outside, so verify it three ways instead: make it contractual, make it traceable, and test the behaviour that differs. Contractually, the BOM including memory brand and grade must be locked, with substitution requiring your written approval. For traceability, require lot identifiers on cartons that tie back to the supplier's incoming material records. Behaviourally, test sustained write speed and capacity — a lower grade rarely shows up as a catastrophic failure but does show up as a steady rate below the quote, or as instability under sustained writes.
Why there is no simple physical check
Memory dies carry manufacturer markings, but they are on the package, and on a finished drive or card the package is inside a housing or under a moulded body. Even where markings are visible, they identify the package, not the die grade inside it.
That means the honest answer to "how do I check" is: not by looking. The verification has to happen in the commercial documents and in the behaviour of the product.
Three layers that actually work
Each covers a different gap that the others leave open.
| Layer | What you do | What it catches |
|---|---|---|
| Contract | Lock BOM; substitution needs written approval | Deliberate mid-programme swap |
| Traceability | Lot ID per carton, tied to incoming material records | Which batch used which material |
| Behaviour | Sustained speed, capacity, stability tests | Lower grade that passes a quick check |
What a substitution actually looks like
It is rarely dramatic. The most common pattern is a reorder that is subtly different: the same capacity, the same look, but slower under a long write, or slightly less stable at the edges of its temperature range.
That subtlety is exactly why it succeeds. Nothing fails inspection; the difference only appears in field behaviour months later, when the original batch and the new one are indistinguishable except by lot.
The practical defence is to test a sample from every reorder against the original sample, using the same method, and to keep that record. A drift that is invisible to the eye is visible on a stopwatch.
The clause that does the work
One paragraph in the purchase order prevents most of this:
> The controller and memory supplied under this order are specified as [brand / grade]. Any substitution requires the buyer's written approval before shipment. Each carton carries a lot identifier traceable to the incoming material record for that lot.
A supplier who will sign that is telling you their BOM is stable. A supplier who resists it is telling you something worth knowing before you place the order, not after.
Sources
- JEDEC — memory device standards and marking
- SD Association — card specifications and performance classes
Figures quoted on this page are from the published reporting listed above. Where a number is an estimate rather than a published figure, it is described as approximate.
Frequently asked questions
Can I ask for the original memory packaging or labels?
You can ask, and a supplier with nothing to hide may provide it for a specific lot. But treat it as supporting evidence rather than proof, because packaging is easy to present selectively. The contractual BOM clause and the lot traceability are stronger, because they create an obligation that survives the shipment.
Will a substituted memory grade always fail a speed test?
Not necessarily on a short test. A lower grade can match a higher one on a small file that fits in cache, and only diverge over a sustained write or across temperature. That is why the test method matters: use a single file large enough to exhaust the cache, and if the product runs hot or cold in service, test at those temperatures rather than at room temperature only.
What can I do if I suspect a swap after the goods arrived?
Document the behaviour first — measured sustained speed versus the original batch, and capacity verification — then raise it with the lot identifier and the test record. A claim supported by numbers and a lot reference is a different conversation from an impression that the drive feels slower. If the supplier will not engage, the lot traceability clause is what gives the claim something to attach to.
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