SSD and the need for SPEED

a 2.5 inch Solid state disk, E-disk from Bitmicro
Image via Wikipedia

Faster, everyone wants to go faster, have a faster computer, a faster disk drive or a faster application. Once a VERY expensive option, the SSD (Solid State Drive) drive has become mostly affordable now they are being made in large volumes. You can get them in all kinds of packaging so you can put the drive into a PCI-E slot or replace an existing hard drive. The most common use for photographer is either as a extra volume or a replacement system volume.

Before we look at the speed of a the SSD, we need to understand how they work and what makes them differently than a traditional hard drive with a rotating plater. The traditional hard drive for years has been made with a motor of some kind spinning a metal or glass platter(s) in a rigid cast metal chassis. They were heavy, took a fair around of electricity to move the platters and it took time to move the heads across the platters. Over the years, the motors were improved, the platters were made lighter and higher capacity and throughput was improved with the new interfaces like eSATA (enhanced  Serial Advanced Technology Attachment) and SAS (Serial Attached SCSI). But even with all the improvements such as 15K RPM drives, glass platters, low power electronics and very sophisticated storage algorithms, they were still a very slow device  when compared to the lighting fast access times of a memory chip.

But memory chips had some issues like they lost their contents when the power was removed and they were expensive in the number needed for any decent capacity. Time passed and now we have FLASH based chips that keep their contents even with power removed, we can write thousands of times to the same locations without the memory location burning out and they are cheap enough we can build an array of chips to supply a reasonable amount of capacity on par with the traditional hard drive.

This brings us pretty much up to date where we can buy a 240 gigabyte SSD drive in an external case with Firewire, eSATA and USB interfaces for about 500 USD. You can buy a bare 500 gigabyte SSD drive with an eSATA interface that drops in as a replacement hard drive for about 750 USD. But why you ask? why spend four times what it costs for a 1 terabyte hard disk drive? In short, SPEED.

The SSD is very fast compared to a normal hard drive, there are no moving parts so the drive is immune to shock therapy and it can be easier on power but not always. Most of us are into the speed for our applications.

For example, I have a 240 GB external SSD from OWC attached using Firewire 800 to a dual quad MacPro tower. My testing of Photoshop, Lightroom and overall usage like file copies showed some very interesting results.

  • VMware Fusion booting Windows XP takes 22 seconds from power on vs. 1:20 for a internal HD
  • Copying 55 GB of data from the MacPro to the external SSD took 19 minutes
  • Photoshop CS5 starts in 17 seconds vs 22 seconds. This does not seem like much till you start using it. Then the speed becomes very apparent between loading large files or files with alot of layers and/or high resolution. It also becomes very apparent in running actions and working with video files which means moving larger chunks of data to and from the disk.

Now the downside to the SSD used to be  the limited lifetime usage of the NAND chips. But that has been overcome to a large degree by over-capacity and by “data leveling” where the data is written out to ALL the chips over time instead of the same group time and time again which is like a traditional hard drive.Each memory location is rated at something like 100,000 writes. However, the cheaper SSD drives are not created equal and one of the corners cut is the over capacity and data leveling.

Where do SSD drives really shine? on the random access times for data. The typical read time is 0.1 ms vs. the 10-15 ms for a normal hard drive which has to move the heads to where the data should be and then wait for the platter to spin around and put the data under the heads. Random access for small files is the key place of performance for the NORMAL user of SSDs. All the bandwidth and throughput of large files is fine but on your computer, it’s mostly small files in random places on the hard drive. If the drive can not perform in this area, you will be hating life and the new SSD that you just spent a ton of money on.

Even the best SSD drives have a limited life time so using them for swap files space is normally a bad idea since the data constantly changes and is rewritten. But for the typical system drive or scratch drive, the SSD can work very well for two or three years of normal use. Any SSD drive will slow down some from the initial speed but they will still be faster than a normal hard drive spinning a disk platter.

If you are a geek and want alot of geeky details on SSD drives, performace and how they really work, check out ANANDTECH and the article I’m linking to. It’s a really good piece of detailed information on SSD drives.

Is this short blog entry a definitive article on SSD drives? not a chance but it should show you that an SSD drive is probably the number one way to improve performance on your editing workstation all the way around. Now days processors are so fast that even a two year old mid line processor is pretty good and ram is so cheap that most systems are now spec’ed with a decent starting point of RAM. So the only real bottleneck to your workflow is the disk I/O speeds. The SSD addresses that in several places and can really boost your output.

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