SSD Write Limit

There has been a lot of discussion, rumour and FUD about the lifespan of the EEE's internal SSD. Forum member Kube made an excellent post in this thread, which is reproduced here for future reference:

Let me offer up some numbers, based on a combination of controlled measurement and meaningful conjecture.

First, I tested my Eee PC's write speed using a program called DiskBench both copying and creating files on the Eee PC's SSD. Depending on the type of file I wrote, my sustained write times varied between 1.1 MB/s and 3 MB/s which is nowhere near the 80 MB/s listed at the link in the OP.

Second, estimating wear leveling is difficult with no knowledge of the Eee PC's methodology. My figures describe perfect wear leveling (unlikely) and 50% effective wear leveling (well below the industry standard) to bracket where the truth likely lies.

Third, predicting actual write time is challenging. As food for thought, if you keep your computer on 100% of the time and write 1% of the time, you will have nearly 15 minutes of continuous hard drive writing each day. If you think the number is higher, you can linearly adjust the numbers in this table. If you think the amount of time you have your computer operating is lower than 100% of the time, then you can adjust the table results downward linearly too.

Assumptions:

1. Wear-leveling is effective to some degree.

2. Write-rates are within the boundaries of this table.

3. Number of bytes and number of sectors (the actual metric being written to) scale together.

4. 1,000,000 bytes = 1 MB is a close enough measure for the time scales in this table.

5. The Eee PC will perform between 100,000 and 200,000 writes to a sector before it fails.

To use the table, choose a sub-table based on wear-leveling effectiveness and total lifetime writes. Enter the sub-table on the line that most closely represents your measured write rate in MB/s. Read across the line to the last column to see how many years until the drive fails (or perhaps becomes unusable/unreliable).

So here's what I'm seeing with the Eee PC SSD useful lifespan (limit) in years. The pairs of lines highlighted in yellow represent the typical range of results I got in my write tests. I continued the table up to a write speed of 10 MB/s just to see how short the lifespan might get.

Example: With the Eee PC SSD, a typical user (6 hours/day, 10% write rate) will write for 36 minutes per day resulting in a useful lifespan of ~25 years in my worst case below (last line in the table). In other words, I'm not going to worry about it.