WTF is Seagate up to with "Multi-Tier Caching Technology"?

I want to upgrade the HDD in my aging laptop to a hybrid SSHD.
(Know any good 1TB or 2TB hybrid 2.5" drives, in the $100 neighborhood?
I'd like to hear recommendations.)

But that's not what this post is about.
See, while I was shopping around, I noticed some funny business from Seagate.

I was skeptical of their reliability because of the high failure rates reported by BackBlaze. So, I was really paying attention to the datasheets.

And I ran across a couple Seagate products with nonsense specs, involving "Multi-Tier Caching Technology (MTC)".
What, you ask, is "Multi-Tier Caching Technology (MTC)"?
Good question. Seagate helpfully describes it like this:

"Multi-Tier Caching Technology delivers snappy performance" ....
"By applying intelligent layers of NAND Flash, DRAM and media cache technologies, BarraCuda delivers improved read and write performance by optimizing data flow, allowing you to load apps and files faster than ever before."

And now you're supposed to be all like:
"Wow, 'media cache technologies'?! Those are my favorite kinds of cache technologies! Here, Seagate, shut up and take my money already!"

The quoted text is from the Overview of a 2TB 2.5" BarraCuda drive on NewEgg: ST2000LM015
It comes with a $99 price tag, and a 2 year manufacturer's warranty.

Similar text describes "MTC" on a 2TB 2.5" FireCuda drive, also on NewEgg: ST2000LX001
It comes with a $120 price tag, and a 5 year manufacturer's warranty.

First of all, is the reliability of the FireCuda drives really that much better than BarraCuda?
Or is the longer warranty just PR, to counteract the negative BackBlaze press?

And secondly, I have a challenge for anyone who actually stops to read this post:
Tell me exactly how much "NAND Flash" is in the "MTC" on these two drives.
I dare you.

It looks like Seagate is trying to see how close to deceptive marketing they can get without actually crossing the line.

What kind of crap is Seagate trying to pull here?
They're selling drives with undisclosed amounts of Flash on board. That number is literally what we're paying for when we buy hybrid drives, and they don't have the courtesy to tell us how much we're getting?

Well, Forum, over to you.
Thoughts? Opinions? Better, non-Seagate options?

PS: I did get actual numbers for quantities of flash on those two drives. But it took two rounds of email with Seagate to get a straight answer. I'll post their answer if anybody wants to see it.

I moved this here, cuz it was just bloating the topic post.

For anyone who wants to take up my "how much Flash" challenge:
I'll make it easy to get started. Here are links to the drive family datasheets:

Hint: It ain't in there. The size of the on-board flash is not disclosed.
Remember how the marketing text that Seagate posted on NewEgg explicitly associates Flash with the BarraCuda drive: "NAND Flash ... BarraCuda delivers".
If you're really paying attention, you'll notice that the BarraCuda datasheet doesn't mention "NAND" or "Flash" at all. Not even once. But those words do appear in some marketing text in the FireCuda datasheet. That's instructive.

Also, a product comparison chart on NewEgg's ST2000LX001 FireCuda drive page says that the FireCuda parts are "Flash-enhanced", while "Flash" isn't mentioned for BarraCuda parts.
And a different comparison chart appears on the ST2000LM015 Barracuda page, which carefully avoids mentioning "Flash" at all, for any product.
These subtle omissions might help keep them on the right side of the law, but they do even more to make it difficult for prospective buyers to figure exactly out what we're getting for our money.

They're certainly doing a good job of suggesting that their BarraCuda drives have "NAND Flash" on-board, as part of "MTC"...which they don't.
The green-labeled BarraCuda Compute drives have no Flash.

If that isn't deceptive marketing, it's about the closest I've seen for anything besides diet pills.

Lack of clear information is never good, naughty Seagate. I honestly have no idea how much NAND is on those drives.

But I do have a slightly older model ST4000DX001. If memory serves I believe it has 64MB old school cache + 8GB NAND. I bought it for capacity more than speed and I've not done any testing but it definitely seems faster than other mechanical drives I've used, at least for gaming. I read some reviews about the technology at the time and they indicated it generally delivered great performance so long as the scale of data you want to keep accessing is not significantly more than the cache size. I've had it about 15 months and it's not dead. That's about all I can tell you.

I looked up technical specs from datasheets I could find online (or as close to datasheets as I could get)

The Barracuda has 128 Mb cache
The FireCuda has 8Gb NAND memory on top of the 128Mb cache.

It appears that they have implemented a controller which keeps track of what sectors are being used the most and pushes them to the cache/NAND until it is told to shut down.


STN000DX001: - p.5.
Firecuda: - p.6.

8 GB NAND flash

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So.... Seagate did a bad job with the PR-Talkie-Talkie in TechSepcs but they do have some kind of Flash Storage?

Seems like all they did was make a faster controller with some new tech they're trying out. If it loads faster, I don't mind the extra 15 bucks. Its no 15000 RPM but it'll do until I can have that.

It's not a new tech. SSHD were popular when SSDs were really expensive. Right now, they may be good for their price tag, but it should be viewed as what it really is: very niche product. Mainly office use, I would say, when you don't have heavy write load. I bet they're using flash as a write cache as well, and what happens under heavy load is that you quickly run out of flash space (because you write too fast for it to destage to HDD in time) and drop to congested worse-than-just-HDD write speed.