Discussion in 'Reviews' started by W1zzard, Mar 15, 2014.
To read this review go to: http://www.techpowerup.com/reviews/Crucial/M550_512_GB/
Chart on the first page has Model: M500 512 GB CT512M550SSD1
Unlike the M500 Series, no overprovisioning is used, so you do get to use all the space the flash chips provide.
Sorry to break it to ya, but this is not true at all. Every single ssd (and flash device) on earth uses overprovising, otherwise it simply wouldn't work. The reason m550 has more usable space is, because they are using much less space for RAIN due to 20nm flash being mature enough at this point.
And yeah, when you buy ssd with 512GB, it actually has 512GiB of raw flash. The difference between GB and GiB is usually used for overprovisioning.
The M500 uses overprovisioning, though, so it only offers up 480 GB instead of 512 GB, like the M550
Again, not true.
While technically the difference between GiB and formatted capacity (roughly 7%) is used as work area for the controller, to store the block bitmap, transaction logs, other housekeeping data, and hopefully use some as spare area as you describe, for consumers "overprovisioning" means "the vendor stole some of the GB capacity to use for improved performance and reliability".
Slides 1-6 should help clear it up.
for consumers "overprovisioning" means "the vendor stole some of the GB capacity to use for improved performance and reliability".
Yeah, but m550 is still using some % of OP for reliability (~1% for RAIN) and some for performance, just like the m500. It's the RAIN percentage that went down with m550, hence giving consumer more usable space. Space for performance is still the same.
So statement "Unlike the M500 Series, no overprovisioning is used, so you do get to use all the space the flash chips provide." can't be correct, because that would mean, there is 0% for RAIN and performance, which is clearly not the case.
I'm looking at a M500/M550 or 840 Evo in the 1TB variety, cant make up my mind. Looks like the M550 is priced the same as Samsung 840 Evo (1TB) and the M500 will drop in price by $60 or so.
Go with m500, its dirt cheap right now and EVO just doesn't justify the price premium. And as an added bonus, you get better flash (3x endurance, but thats a non issue anyway even with TLC).
But if you need a "performance" drive and you dont care about $/GB, you're looking at the wrong drives anyway
I'd go with the M500 too, due to its price
Yeah, right now m500 is really a steal (it runs for ~180€ here in EU for 480GB). m550 just doesnt make much sense price wise, as its not _that_ faster than m500.
Maybe if prices come down for m550 or if crucial has some tricks up its sleeve to improve performance (as they did with m4) i see no reason for recommending m550.
This review is missing one important feature of this ssd, namely the power loss capacitors. The m550 (same as the m500) has power loss capacitors which protects the ssd from data loss in case of a power outage or other unexpected behaviour. Personally, I think that this feature is a huge plus and should be mentioned in the review and conclusion (in the thumbs up list). Althought the EVO is faster than both the m500 and m550, I would always choose the m500/m550 because of the power loss protection. Besides the increased performance of the EVO will not be noticable during day-to-day use for most users. Looking at the price/performance ratio, there is no doubt the m500 is the way to go.
Any idea how to test this? Just cutting power seems like a bad idea(tm).
To be honest, I wouldn't know how to test that.
I have read other reviews which mention the power loss protection but none of them actually test this feature
I agree. This is something that TPU could investigate further or even make an exclusive feature (like TheTechReport.com does with their SSD endurance testing). Yours could be "SSD data reliability/retention test" or something similar.
I guess cutting the power as soon as a command is sent to the SSD to write down a file would do it, though I have no idea how to implement that. Perhaps someone who has experience in this area can enlighten us?
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