Not much difference between 256GB and 512GB ssd

I have recently upgraded to 512GB Crucial MX100 ssd but the readings are almost similar to 256GB ssd, I am not too bothered but inquisitive.

 

Read speeds are essentially the same.

However, the higher capacity SSD has better write performance. Most SSD ranges show the same characteristic which, IIRC, is because more capacity also has more cache.

John

 

Thnaks John.

 

While some model lines may have more cache going from 240/256GB capacity points to the 480/512GB capacities, the major contributor to the speed increase (overall, not in each individual benchmark) is because the number of channels and the interleaving of those nand channels is much better optimized for the larger capacities.

The number of channels is easy to understand: if a controller is able to use a nand package on each controller channel (usually 8 with todays SSD's) then the parallelism offered increases performance for file sizes greater than the nand block used.

The optimal interleaving of those nand packages (for example, two or more nand packages on each controller channel) allows further parallelism (think RAID0) for each nand. This increases the performance further. The better SSD's out there optimize the firmware for the specific model and capacity.

Usually, the snappiest SSD's are the 240/256GB SSD's while the actual workhorses are the ones in the capacity point above that (without loosing too much snap, either, except on benchmarks).


With each nand chip able to deliver between 20 to 200 MB/s (depending on the nand generation and quality) on it's own, having the controller channels fully populated and each channel optimally interleaved it is still vital to optimize those design parameters to get the most real world performance from our SSD's.