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Samsung 840 EVO in "different flavors"

BonzaiDuck

BonzaiDuck

Lifer
Scour the "OC'ing" forum and you'll see that I had a peculiar, infrequent instability problem. It looks more and more like the OC'd RAM settings with CMD=1. Now that's behind me . . .

The problem made me contemplate replacing RAM with a faster two-stick kit. Since purchases from the Egg can offer me an advantage under "Preferred Account," I look to consolidate purchases to reach an "advantage threshold." And for the last year, I'd been looking at the Samsung SSDs.

My ISRT configuration just seems rock-stable and working perfectly, so no need to spend any money at the moment.

HOW_EVER -- I get regular "Soch-a-dea-ull!" notices from the Egg -- daily. They're offering the 840 EVO 500GB SSD for $0.60/GB, or just over $300.

BUT -- it's an "MLC" drive. I've begun to notice that the 840 series includes models that are "MLC" and others that are "TLC."

Isn't TLC better?
 
BonzaiDuck said:
BUT -- it's an "MLC" drive. I've begun to notice that the 840 series includes models that are "MLC" and others that are "TLC."
Click to expand...
840 = TLC
840 Pro = MLC
840 Evo = TLC that can be partitioned to work as pseudo-SLC.

Isn't TLC better?
Click to expand...
No. Typical ~20nm TLC can take 1000+ writes before errors/retention may become problems (see Techreport's endurance test, FI). Typical ~20nm MLC can take 3000+ writes, better binned 5000+, and writes faster. SLC is quickly becoming such a niche product* that I can't even find p/e ratings with a quick search--probably around 10,000+, though.

At the same size die, MLC has about 2x the capacity of SLC, and TLC about 3x. So, TLC is much better for Samsung, because it costs them a bit less to produce (go read the intro to the 840 Evo SFF review, here). Given typical usage, and with TR's testing, I wouldn't worry about endurance for most users. At the same time, all else being equal, I'd get an MLC drive, instead. Toshiba, Sandisk, and Crucial have been quite competitive with good non-SF MLC SSDs, usually cheaper than the 840 Evo.

* It would not surprise me if future "SLC" products are just MLC factory-programmed to be in pseudo-SLC mode over the whole chip, since the market for SLC has been shrinking, and will likely continue to do so.
 
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Cerb said:
840 = TLC
840 Pro = MLC
840 Evo = TLC that can be partitioned to work as pseudo-SLC.

No. Typical ~20nm TLC can take 1000+ writes before errors/retention may become problems (see Techreport's endurance test, FI). Typical ~20nm MLC can take 3000+ writes, better binned 5000+, and writes faster. SLC is quickly becoming such a niche product* that I can't even find p/e ratings with a quick search--probably around 10,000+, though.

At the same size die, MLC has about 2x the capacity of SLC, and TLC about 3x. So, TLC is much better for Samsung, because it costs them a bit less to produce (go read the intro to the 840 Evo SFF review, here). Given typical usage, and with TR's testing, I wouldn't worry about endurance for most users. At the same time, all else being equal, I'd get an MLC drive, instead. Toshiba, Sandisk, and Crucial have been quite competitive with good non-SF MLC SSDs, usually cheaper than the 840 Evo.

* It would not surprise me if future "SLC" products are just MLC factory-programmed to be in pseudo-SLC mode over the whole chip, since the market for SLC has been shrinking, and will likely continue to do so.
Click to expand...

TechReport has always given reliable reviews, IMO. The other thing I discovered recently and hadn't thought of: You can't just remove an SSD from a system and expect it to hold the data for six months. At least -- that's what I thought I read somewhere. . . .
 
Cerb said:
Consumer flash should hold data for at least one year, offline, at room temp, if it hasn't used up its rated p/e cycles, and much longer if not written to very much (which will be the common case). But, the reduction due to higher temps is worth considering, as it is far from linear (slide 27, below).

http://www.jedec.org/sites/default/files/Alvin_Cox [Compatibility Mode]_0.pdf
Click to expand...

That relieves some uncertainty from the question and what I heard as an answer earlier.

BTW. Zappa's father was my high-school math teacher: "Lissen, fellas -- lemme tell ya how to do this limit problem without the textbook." I had to make extra effort in college calculus the following year. Maybe he should've "done music" instead, but I thought I heard where the two disciplines use the same parts of the brain. Maybe . . . maybe not. It was 50 years ago!
 
Cerb said:
No. Typical ~20nm TLC can take 1000+ writes before errors/retention may become problems (see Techreport's endurance test, FI). Typical ~20nm MLC can take 3000+ writes, better binned 5000+, and writes faster. SLC is quickly becoming such a niche product* that I can't even find p/e ratings with a quick search--probably around 10,000+, though.
Click to expand...

The SLC I'm familiar with is good for 150,000 P/E cycles.
 
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