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SSD formatted capacity off (by more than usual)

Last response: in Storage
May 30, 2009 6:19:38 AM

Yes, I know 64GB is a marketing term and the actual drive should come out to 59.6GB, but my 64GB Samsung MCCOE64GEMPP is showing up as 55.9GB. Any idea why this SSD would be missing so much space?
a c 126 G Storage
May 30, 2009 11:30:09 AM

Its probably 60GB, and if you calculate the 1000/1024 difference you would have 55.87GiB. Keep in mind that disks including SSDs keep some capacity to themselves for internal usage, making the SSD much faster in random write situations.
May 30, 2009 3:57:30 PM

That makes sense, but why would Samsung sell a 60GB drive marked as a 64GB drive? That sounds illegal to me.
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a c 126 G Storage
May 30, 2009 4:43:05 PM

Since flash memory just follows the 1024-rules of numbers (powers of 2) there should be no reason a 64GB drive is actually 64GiB (and not 59,6GiB). So the first models were labeled 32/64/128/256 etc. But they soon found out its better to stick to known HDD capacities. Not only because it makes comparing more easy, but also because the SSD can use reserve flash cells both to accelerate writing, and perform wear-leveling and recovery operations.

In other words, your SSD has more capacity than it will let you use, which is necessary to make a good SSD.
a b G Storage
May 31, 2009 5:12:29 AM

One bit of (recent) news which might be of interest...
IBM now offers an SSD option for some of it's Power Servers, but only 69Gig of the 128Gig SSD is useable, the rest is used for wear leveling to maintain performance and ensure an "acceptable" product life.

a c 126 G Storage
May 31, 2009 1:27:46 PM

That's alot of overhead, its probably not due to wear-leveling, but likely they use a huge pool of empty flash cells to accelerate random writes. But IMO it should be labeled as a 64GB disk instead, its all about usable capacity, not raw capacity.