What to Look for in a Solid State Drive (SSD)

Current Hard Drives are using the same basic technology that drives used beck in the 1950s. Sure, size, speeds and interfaces have changed but its still a platter spinning with a read/write head hovering over it like a needle on a record.

Solid State Drives (SSDs) are the next wave in Hard Drive technology. With no mechanical parts, no noise, less power requirements and less susceptibility to damage, its a no brainer that they’re better. However, SSD technology is still very much on the cutting edge and not all perform equally well.

Here’s a quick rundown of what you need to know about SSDs in order to purchase one that works well for you.

Advantages and Disadvantages:

Solid State Drives aren’t all sunny days, rainbows and roses. While they have advantages over conventional Hard Drives, they also have disadvantages.

The Advantages:

- Low power consumption.
- Silent operation.
- Low heat production.
- No moving parts to fail.
- Less susceptible to damage.
- Can handle motion and vibration.
- No read/write head moving around during random access.
- No fragmentation issues.

The Disadvantages:

- Price,
- Capacity.
- Write speed much slower than read speeds.
- Not all drives read / write performance is the same.
- Limited number read / writes in a memory cell’s lifetime.
- Wear leveling and secure wipe / encryption issues.
- Performance degrades with use from wear leveling and write combing.

Taking the disadvantages into consideration, not all drives perform the same. Some perform very well and are worth the expense. Others give Solid State Drives a bad name. Think of it like finding a really cheap USB drive a few years back, thinking you’re getting a great deal and then you find out its USB 1.1. Taking a few minutes now to research SSD performance is well worth it.

What to look for when purchasing:

The first thing to consider in a SSD is whether it uses Single-level cell (SLC) or Multi-level cell (MLC) technology. SLC drives perform much better and are more reliable than MLC drives. However, SLC drives are more expensive than MLC drives. Since SLC uses one bit per transistor, its faster but requires more transistors per GB than MLC, which uses two bits per transistor. Its a toss up because a high performance SLC drive can get expensive.

Next, you need to know what controller is onboard the SSD. This makes a gigantic difference and is the reason all SSD drives are not equal. What you want is either the Intel X25 or Indilinx controller – preferrably Intel’s X25. Accept no others. If you’d like the technical details why, here is an incredible article from Anandtech.

Finally, you want to see some specs on Cache size and Read / Write speeds. Look closely at the write speeds for small files. If you’re using this SSD as a system drive in a laptop, it will be writing small files constantly during normal operation. Bad performance here could really impact your system. Again, looking at Anandtech’s benchmarks, you can see the difference between Intel and the Indilinx, and SLC vs MLC.

Notice that Samsung doesn’t fare very well in his review. This is very important because if you order the SSD upgrade from Apple for a MacBook Pro or Air, Samsung supplies the SSD drives for Apple. You are much better off getting an Intel or an Indilinx based OCZ Solid State Drive and doing the upgrade yourself.

Basically it all boils down to three things:

- SLC is better than MLC but more expensive.
- Controllers make a huge difference in performance.
- Currently, Intel’s SSDs have a huge performance lead.

What should you do?

Since SSDs are still at the beginning phase, there’s still kinks to work out. Right now, I see their primary advantage as being able to withstand motion / vibration without corrupting your data and failing – like conventional drives often do. SLC is expensive compared to MLC and right now Intel has the best performance. OCZ is catching up with their latest offerings and I believe that within another year, SSDs will reach the tipping point when they become more mainstream.

In the meantime, if you want SSD performance and reliability right now, I recommend the Intel X25M 80gb Solid State Drive. It has 80gb which makes it large enough to use as a laptop drive, Intel’s X25 controller and MLC. Its not so expensive, has decent performance and more important, high ratings in both Amazon and NewEgg’s reviews. Its a little more than the $130 40gb Intel X25V but the write speed is twice as fast and frankly, 40gb isn’t very much space for a laptop system drive.

Whatever you do, if your Mac has an easily accessible Hard Drive, don’t get your SSD though Apple.

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