The SSD in PC video editing

Super fast and also super fast back to slowly?

The latest version of the "hard disk" is the so-called SSD, Solid-state disk, which’s experience is characterized by very high data transfer rates and where application-loading will get an extreme acceleration.
However, caution is advised because this new storage medium also has its pitfalls. In brand new condition, everything works fine, but the longer and more often one uses its SSD, the slower and unfavorable it gets until after a relatively short time, it’s even worse than a conventional magnetic hard disk drive (HDD).
Under the right conditions, when the remaining components of the computer allowing it and the software properly configured, you can prevent this and enjoy the thrill of speed for a long time.
In contrast to VIDEOSTATION^®, this is far from being given to any other workstation.

The problem

In order to achieve low access times SSDs consist of flash memory, which, unlike the usual hard disk is organized in blocks. A block of memory that is usually sized 128-512 Kbytes is always written as a whole, regardless of how much you have changed. In addition, only empty blocks can be written to, if a block already contains information, it must first be emptied.
While a new SSD still has a lot of empty blocks, there is no problem, and the SSD provides very high performance. The more data travels over to the SSD, the fewer blocks are still quite empty. Although the SSD e.g. is half full, it does not mean that half of the blocks are empty, it is more likely that all blocks are filled 50%. The reality lies somewhere in between.
Now, if the SSD controller wants to add something to a block that already contains data, it first has to read from the block and park the data in the buffer memory of the SSD, then the block must be deleted and after that, the new data, together with the parked old information is written to the (now) empty block.

Solutions

To address this problem, combination of "Trim" and "Native Command Queuing" short "NCQ" is used. It is important to ensure that both, the controller of the SSD, as well as the on-board SATA Host Adapter of the PC support this features, which is the case at VIDEOSTATION^®. Also a special feature of VIDEOSTATION^® is the ability to run RAID and single disks simultaneously without losing these features. To retrofit a SATA host adapters should be avoided in this case, as it so often comes to slowdowns and incompatibilities.

NCQ – Tetris for storage-blocks

NCQ is a feature which was originally designed for HDDs. A hard disk typically performs write commands in the order in which they arrive. With NCQ the hard disk controller has the opportunity to buffer up to 32 write commands to rearrange at will and then execute them in the new order. In SSDs, this is used to divide the data to be written so that they must be distributed to as few blocks as possible because it makes no difference how much data you write to a block, but how many blocks you write.

Trim – Takes out the trash

When Windows deletes a file, it usually just makes a note, "where the file is located, there is now nothing (important) left" and if the space is used the next time, the disk just overwrites what stood there. In SSDs, this is not practical, since it can only be written directly to empty cells. A "just write over it" here means read only, then delete, then write the new data with the rest of the old trash into it.
If Trim is supported and turned on, Windows tells the SSD-controller while deleting that "this data has now been deleted" which puts the controller in a position to clean up and preempt the block, so the next time you write to it, data can be written "just like that".

Alignment - Everything in its place

As already mentioned, the memory on SSDs is organized in blocks and it is existentially important to write as few blocks as possible. That is why, when it comes to creating partitions on SSD, you have to make sure that they are properly "aligned".
The file system of the partitions has so-called "smallest allocation units" and is therefore at a logical level also organized in blocks. The danger is that the logical blocks of the file system and the memory cells on the physical layer overlap if they are not aligned correctly.
Imagine, the file system would be oriented so that a block always reaches from the center of a memory cell to the center of the next memory cell. Now if data is stored in this block, it must be written to two cells by the SSD. In comparison, when each block reaches from the beginning of a cell up to its end, only this one cell has to be written.
SSDs without proper alignment have only 50% of their writing speed and can only survive half the number of write cycles compared to SSDs where the alignment is correct, as in the VIDEOSTATION^®.

     
Benchmark results of a VIDEOSTATION^®-SSD without a proper alignment (left) and the results of the same SSD with the correct alignment (right).