Solid State Drives (SSDs) FAQ
This page is meant to answer various Frequently Asked Questions that you may have about SSDs (Solid State Drives).
Who are SSDs for?
SSDs are for you if you want:
- Much faster OS boot, Shutdown, Sleep and Hibernation
- Much faster program and game loading, meaning that you don’t have to wait as long for your program or your game to load.
- A system that feels more responsive.
A quick recap on what a SSD is:
You know those flash chips that are used in USB sticks and SD cards? A SSD is basically several of those chips working in parallel with a controller to bring you higher speed.
There are many advantages to a SSD compared to a traditional spinning mechanical hard drive, such as:
- No noise because of no moving parts.
- Lower heat emission compared to hard drives.
- Lower power consumption and as a result: Longer battery life for laptops
- Much more resistant to shock and vibration, making them less likely to fail from that.
- Much lower latency (~0.07ms compared to 7-9ms).
- Much higher transfer rates for reading and writing files in all type of scenarios.
What about those reports of SSDs slowing down over time?
They are true, but let me clarify this quickly for you: SSD are similar to hard drives in the way that they delete files: They don’t. They simply flag the files as deleted.
What’s the problem with that? With a hard drive, when you want to use the space occupied by the previous file, the hard drive would simply overwrite it. In the case of a SSD, it needs to erase the file prior to writing again.
Until recently, SSDs would delete the file right before writing the new one. Needless to say, this slows down write operations a lot, especially as your SSD gets filled up and you need to erase pretty much any previously deleted file to write new data.
TRIM
TRIM changed that though. What TRIM does is erase the file right away, allowing you to write at full speed without waiting to erase previously used space.
All the recommended SSDs in this guide support TRIM.
Now, to use TRIM, you need a OS that supports it, such as Windows 7, Mac OS X and some variants of Linux being the only ones as far as I know. You also need a SSD that supports TRIM obviously.
If you want to learn more about SSDs and TRIM, I highly recommend The SSD Anthology: Understanding SSDs article from Anandtech, a very complete and detailed article on SSD, a must read in my opinion. Also from AnandTech, The SSD Relapse: Understanding and Choosing the Best SSD is another must read if you want to learn more about SSDs.
TRIM with RAID:
From AnandTech:
“For months now you all have been asking me to tackle the topic of RAIDing SSDs. I’ve been cautious about doing so for a number of reasons:
1) There is currently no way to pass the TRIM instruction to a drive that is a member of a RAID array. Intel’s latest RAID drivers allow you to TRIM non-member RAID disks, but not a SSD in a RAID array.
2) Giving up TRIM support means that you need a fairly resilient SSD, one whose performance will not degrade tremendously over time.
So in short:
You can use two or more SSDs in RAID, you just need to pick the right SSDs. My recommendation would be use either one of these, in this order:
- A SandForce based SSD, such as Corsair Force/Force 3/Force GT series or OCZ Vertex 2/3/Agility 2/3.
- Toshiba controller based SSDs (Mostly some Kingston models).
- 2nd generation Intel SSDs
You can use other SSDs for RAID, but I wouldn’t recommend it, since performance will degrade over time, slowing down the SSDs to a crawl which is not something that you’d want when you pay for two or more SSDs.
Intel to add TRIM Support for RAID 0:
Great news! The TRIM feature will be enabled for RAID0 setups in Intel’s upcoming RST (Rapid Storage Technology) 11.5 driver.
Quoting from this AnandTech news: “Intel’s release notes for Rapid Storage Technology (RST) 11.5 Alpha version reveal that they have plans to add TRIM support for RAID 0 arrays in the next version of RST.” Intel is expected to release the RST 11.5 driver sometime in Q2 2012.