Whats the difference between 64 and 60GB SSDs?

[DesiPower]

I am planning to get a SSD for the 1st time, never gave any thought about it in the past so have no idea about them. Budget is about $100 so looking at 60 - 64GB ones. Here's my question...

Intel has multiple of 10, other have multiple of 8, some companies like Corsair have both! Whats the difference? is one technology superior or newer than another? Since Intel used 10s I was leaning towards 10s too, not based on any scientific facts... please help.

Also, which make do you guys prefer? Newegg has almost same kind of reviews for Corsair, Crucial and OCZ, those are the only three I am looking at right now... I am open to suggestions..

 

[Seero]

I am planning to get a SSD for the 1st time, never gave any thought about it in the past so have no idea about them. Budget is about $100 so looking at 60 - 64GB ones. Here's my question...

Intel has multiple of 10, other have multiple of 8, some companies like Corsair have both! Whats the difference? is one technology superior or newer than another? Since Intel used 10s I was leaning towards 10s too, not based on any scientific facts... please help.

Also, which make do you guys prefer? Newegg has almost same kind of reviews for Corsair, Crucial and OCZ, those are the only three I am looking at right now... I am open to suggestions..

Size of memory always comes in 2^x bytes. Since 1 mb is 1024(2^10)kb, and 1gb is 1024mb, if you see 64(2^6)gb, then it is the correct size of the memory.

If I am not mistaken, those drives that are being sold as 60gb does have 64gb of memory, but only 60gb available. Back at Gen1, alignment of the drive has direct impact on the performance of the drive. If you tried to fdisk a 60gb SSD, you can get that extra 4Gb out, but then performance will tank badly.

I don't know if the same thing applies nowadays as SSD design and controller has improved. Those there are being sold as 30, 60, 120gb actually have 32, 64, and 128gb memory. The missing 6.6667% space are either lost due to alignment, being used as reserves for garbage collection, or host alien code
that will eventually kill us all.

If I am not mistaken, some vendor likes to sell the total memory size, while some likes to sell total available memory size. This leads into another question, "do user need to align drives that are being sold as 32,64,128gb?"

I don't know the answer to that question, but I will still align the drive.

 

[DesiPower]

Thanks for the explanation, if I understand this correctly then, a well aligned drive will loose 6.66% so I should be looking at 60GB ones... I am not worried about whats in that 6.66% of the drive... nothing that my tin foil hat cannot take care of.

 

[Seero]

Thanks for the explanation, if I understand this correctly then, a well aligned drive will loose 6.66% so I should be looking at 60GB ones... I am not worried about whats in that 6.66% of the drive... nothing that my tin foil hat cannot take care of.

What I am saying is, some drives are sold as total memory (64gb), and some are sold as total available memory (60gb). In other words, they are the same.

Other than Intel SSDs, all other SSDs are very similar in design. If it is advertised as 60 or 64gb, then they probably use 16 34nm MLC Nand flashes, and each Nand flash is 4gb. That is, 16x4 = 64gb. Newer SSD may use 25nm MLC Nand flash, which is 8Gb in size, so 8x8 = 64gb (I think 25nm is only used in 120gb or above drives). Intel use 20 34nm Nand flashes, which is 20x4 = 80Gb.

As you can see, they are the same, but being marketed differently.

Side note, nothing to do with SSD :
I got a HDD drive that was advertised as 80gb a long time ago, but in fact there is only 74.5Gb, 80,015,491,072 bytes. I didn't lose anything, just extremely confused as "Where the F did 5.5gb go?" Of course, later I have learned that they use 1gb = 1000^3byte instead of 1024^3byte.

 

[Burner27]

YHPM Desipower

 

[Emulex]

remember there is reserve space on ssd's too. the sandforce 64gb drive can reserve out to 50gb or 55gb usable. the intel x25-V 40gb comes out to 37gb usable. so you have to take that into consideration too. 148gb is what i get out of my x25-m 160gb formatted.
so x25-m is like 7-8% less formatted but my microcenter G2 64gb is 14-15% less formatted.

 

[EarthwormJim]

There's no difference in actual capacity.

The difference is just in one manufacturer being dishonest with how it calculates gigabytes, and the other being faithful to the true definition.

A gigabyte is 2^30 bytes, not 10^9 bytes (despite what hard drive manufacturers like to think). The 64gb drive manufacturer is going by 10^9 bytes as its definition of a gigabyte, while the 60gb drive manufacturer is using 2^30 bytes as its definition.

Both drives really have 64,000,000,000 bytes.


Intel uses multiples of 10 due to their controller design. Their controllers have 10 channels, other manufacturers have 8 channels. So depending on the desired capacity, they'll put one NAND module (or more) on each channel.

 

[T_Yamamoto]

There's no difference in actual capacity.

The difference is just in one manufacturer being dishonest with how it calculates gigabytes, and the other being faithful to the true definition.

A gigabyte is 2^30 bytes, not 10^9 bytes (despite what hard drive manufacturers like to think). The 64gb drive manufacturer is going by 10^9 bytes as its definition of a gigabyte, while the 60gb drive manufacturer is using 2^30 bytes as its definition.

Both drives really have 64,000,000,000 bytes.


Intel uses multiples of 10 due to their controller design. Their controllers have 10 channels, other manufacturers have 8 channels. So depending on the desired capacity, they'll put one NAND module (or more) on each channel.

someone did his homework

 

[WaTaGuMp]

The difference is 4gb, what do I win?

 

[DesiPower]

OK, so it seems, performance wise there should be no difference, its just a matter of representation or configuration.

I am planning to go with Crucial, they seem to have the best reviews at newegg. I will probably go with "Crucial M4 CT064M4SSD2", Crucial also has C300 which is a tad more expensive, anyone knows whats the difference, M4 vs C300?

 

[sub.mesa]

It is a common misconception that 64GB SSD drives use the full capacity and thus physically have 64.000.000.000 bytes of data; this is not true.

All NAND and DRAM memory use powers of 2; and as such 64Gbit chips are 8GiB in size; not 8GB. With 8 of these chip you get a total capacity of 64GiB; not 64GB.

64GiB = 64 * 1024 * 1024 * 1024 = 68.719.476.736 bytes
64GB = 64 * 1000 * 1000 * 1000 = 64.000.000.000 bytes

So all 60/64GB SSDs are physically 64GiB, but keep a portion of that space invisible for use as spare space, for system data (mapping tables) and for reserve NAND pages if they become bad (equivalent of reserve sectors).

Intel and some other manufacturers use only the difference between GB and GiB for invisible spare space; which is about 6.8%. Other manufacturers use additional spare space which helps in maintaining the performance of an SSD over a longer period of time. In the past 64GiB SSDs were even sold as 50GB, and 128GiB SSDs sold as 100GB. This means more than one third of the physical space is in fact invisible and used as spare space.

Currently this kind of high spare space is only found in professional SSDs which receive a lot of random write requests. Normal consumer drives need alot less spare space. However, due to their design, all modern SSDs have spare space; no SSD use the full capacity.

 

[Ben90]

Its actually really annoying that some companies label their drives as 60GB. I know they are trying to be honest, but they should just stick to the adopted way. Now we have to broaden our searching terms to 64GB AND 60GB drives. Much simpler to stick to one system.

 

[Voo]

There's no difference in actual capacity.

The difference is just in one manufacturer being dishonest with how it calculates gigabytes, and the other being faithful to the true definition.

Yep, as we all know "giga" has a long tradition of standing for 2^30 (just as a kilometer is obviously 1024 meters). The definitions for giga and co have long been adopted by most official associations like the IEEE and as a matter of fact several areas in CS have used the SI prefixes correctly for decades (ega gigabit ethernet connection isn't 2^30bit but 10^9)

As long as it's clear what is meant with it from the topic everything's fine, but especially for storage where there's always confusion about this, using the standard nomenclature would be a really, really good idea

 

[Burner27]

OK, so it seems, performance wise there should be no difference, its just a matter of representation or configuration.

I am planning to go with Crucial, they seem to have the best reviews at newegg. I will probably go with "Crucial M4 CT064M4SSD2", Crucial also has C300 which is a tad more expensive, anyone knows whats the difference, M4 vs C300?

The M4 and the C300 use the same Marvell controller. The difference is the firmware they use. The M4 uses a FW that is geared more towards higher sequential reads/writes numbers (large file transfers) whereas the C300 is geared more towards higher performance with the 4k random reads/writes (typical OS performance). You would 'usually' use an SSD of the size you're going to buy for OS use.

The other difference is the NAND flash they both use. The C300 uses 34nm flash whereas the M4 uses 25nm NAND flash. Supposedly the 25nm NAND flash is cheaper to manufacture and therefore the savings get passed on to the consumer. The 25nm process has lower total write cycles (~3000) compared to the 34nm process (~5000). According to the manufacturers, this shouldn't affect the overall lifespan of the drive because a 'typical user' would not ever come close to using an SSD in a way that would use up those writes cycles.

Hope that helps.

 

[DesiPower]

Oh yes, its this is great info!! Thanks!!!

darn it, WTF, they raised th price of M4 for $45 ...:'(

or maybe that was the original price, I missed the discount...