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Don't confuse the interface for the drive itself. In most consumer tech the interface is way beefier than it needs to because of marketing. You can see that right now with PCIe gen 5 drives which could just as well be gen 4 except that no one would be talking about them if they were.

For that matter, how many drives are actually capable of maxing out SATA's 6Gbps?

There are architectural reasons for moving away from SATA I know, but the raw bandwidth is there.

A $50 budget NVMe will do that 5x over on cached writes or reads just fine. Remember SATA is 6 gigaBITS per second and drive speeds are often measured in BYTES per second. After overhead you only get ~500 MB/s if your SSD is attached via SATA, quite a few of the dirt cheap SATA drives in the article even seem to be running into that limitation at first.

SATA is 6 Gbps, not 6 GBps. Tiny cheap drives like the ones in this article are the only ones that struggle to saturate a SATA link during sequential transfers. Any NVMe drive 1TB or larger will offer sequential read performance several times higher than SATA could handle, and if it's a TLC drive rather than QLC the sequential write performance will also generally be at or above the SATA limit even after the SLC cache runs out.

You might be confusing Gigabits for Gigabytes. 6 Gbps means 6 gigabit/s which translates to about 550 megabyte/s sequential in practice.

M.2 PCIe 3.0 x4 is 32 Gbps (4 GB/s), the same with PCIe 4.0 is about 64 Gbps, and PCIe 5.0 gives you 128 Gbps. 5/10/20 times faster than SATA 3, respectively.

Hard drives manage a bit above 250 MB/s nowadays, sequential. MLC and TLC SATA SSDs can usually saturate the interface, but QLC SSDs are generally much slower with write speeds between 50 and 150 MB/s.

> You can see that right now with PCIe gen 5 drives which could just as well be gen 4 except that no one would be talking about them if they were.

Where? I've only seen a few models get talked about, and they could all easily bottleneck a gen 4 connection.

It's still hard to find a use case, but the interface is not overspecced compared to the flash and controller on the ones I've seen.

Yes, the problem is it's hard to tell what the underlying drive is. I read reviews of one SATA drive, but it seems they swapped out the actual chips but kept the same model number, as all the reviews said it could saturate it, but mine can't, despite having the same model number.

> And to top it off I just got a 256GB M2 Macbook air for travelling which has horribly crippled IO perf compared to the other models, which I didn't realise until after I bought it.

When buying anything from Apple (be it an iPhone or a Macbook), always need to make sure it's at least one notch above minimum storage tier.

For example, if the lowest tier is 512 GB, should go for 1 TB storage.

This helps both performance and the longevity.

What? Why? I'd expect the opposite, which is that the most popular variant would be the most stable and well-tested.

They didn’t speak to testing or stability, I doubt it differs at all. If you want your soldered storage and memory having tech purchase to last longer you upgrade at the time of purchase from the base spec.

Because how many physical storage chips has a direct correlation to speed. Often the lowest tier may have a single chip- so the throughput is limited to that chip's throughput potential. Multiple chips are basically like raid 0- you spread the read/writes over multiple chips and get the aggregate speed. You also have more 'sectors' to spread errors over as the chip degrades over time.

If the goal is performance and longevity, I can see how multiple chips might help with performance. But what about longevity? It seems that more chips means more things that can break, and when one of them breaks your whole hard drive will be broken. I guess the question is what's more likely, one of one chips breaking, or one of two chips breaking? Given what you said about read/write "spreading over" chips, maybe it's not so simple as assuming more chips equates to higher chance of failure.

More NAND dies means a given number of TB of writes will require doing fewer write/erase cycles per memory cell, because you have more memory cells.

NAND flash almost never fails a whole die at a time. An individual NAND die fresh out of the fab will already have a few defective memory cells, and as the drive is used, more write cycles will result in more memory cells failing and being retired. This gradual, partial failure is fundamental to how SSDs manage flash memory.

> It seems that more chips means more things that can break

Nope.

> I guess the question is what's more likely, one of one chips breaking, or one of two chips breaking?

Doesn't matter. In each case you lose your data. And if the system is so frail what addition of another chip rises the failure rate through the roof then the talk about the reliability of such system, no matter how much chips it have, is moot.

The performance of that cripled Macbook is still so much better than this cheap crap, it's still perfectly fine and longevity is also likely fine.

> but I cannot understand how those do 2000MB/sec no problem, but cheaper drives struggle with 100MB/sec.

No DRAM cache and less flash chips, means less throughput. All these cheap SSDs I've tested only have one physical flash chip.

High-performing SSDs often spread their capacity over multiple chips so they can leverage the individual chip bandwidth and thus have more throughput.

But there are likely much more factors that I'm not familiar with.

> And to top it off I just got a 256GB M2 Macbook air for travelling which has horribly crippled IO perf compared to the other models, which I didn't realise until after I bought it.

Do you really feel the crippled IO perf? I mean this machine still has read rates between ~800 and 1700 MB/s. Thats not exactly the definition of slow.

I debated about spending the extra whatever to go to the larger/faster storage due to this problem. In the end I went for the base/lowest cost MBA M2 because it's still plenty fast day to day for me and only on rare occasions would I need that extra bump in speed. Even then the difference is probably seconds rather than minutes or hours.

The most ridiculous part of all of this is that they're pushing a pro machine with crippled IO performance.

Not for writing and reading actual files, no. But the 8GB of ram means it can swap to disk quite easily, and the faster speeds really make a difference with that. My M1 mac mini I got to play around with the new arch feels much much faster when memory constrained because of this.