Same write endurance for SSD models with different capacity?

Just reading Crucial M550's spec and noticed everyone in the line-up rated at "72TB Total Bytes Written". Aren't the bigger ones with more physical NAND more resistant to writing wear?

 

Look at the Scandisk Extreme Pro and Samsung 850 SSD...

 

Yes it is, more NAND=more cells to perform wear levelling. The endurance of an SSD theoretically scales linearly with it's capacity. In practice, it isn't quite the case due to imperfect wear levelling and write amplification but the concept is there. I haven't a clue why Crucial has the same spec for all their drives because this technically disadvantages the higher capacity models.

 

I think its because Crucial's M550 drives are budget drives... They're probably trying to keep costs as low as possible in that manner...

 

The specs a manufacturer puts there are just minimum specs, not predicted real-world specs. The reason is because those numbers will be the basis for warranty claims.

Technically, will a drive that has twice the NAND capacity have twice the maximum lifetime write capacity? Yes.

But it sounds like this is a case where Crucial didn't bother updating specs for each individual drive capacity, and erred on the conservative side for those numbers.

 

Looks like even the 16nm MX100 series is rated as the same. So the number doesn't make much sense technically.

Edit: Some industrial SSDs with comparable NAND and capacity are rated at a few PBs. Crucial must be just setting warranty limits here.

 

They're budget drives supposed to last 2-3 years... Long term endurance hardly seems to be a priority hence...

 

Exactly! Warranty limits and a blanket policy like your auto.