Questions about Crucial MX500 SSD Smart Attributes

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Kilobyte Kid

Questions about Crucial MX500 SSD Smart Attributes

I recently acquired a Crucial MX500 500GB SSD (Firmware: M3CR020). I have a few questions about certain SMART attributes as reported by the drive (for example through the Linux utility smartctl/smartmontools).

 

1) What correlation is there exactly between Host Program page count and Total Host Sector writes? I've found that the bytes/page calculation gives a graph showing a value that tends to decrease over time and increase in steps whenever a large amount of sequential writes occurs, as in the graphed example. Why does it decrease over time anyway?

MX500_bytes-page.png

 

 

2) Can you confirm that the real Write Amplification value is calculated as [1 + (Background Program Page Count / Host Program Page Count)] as described here for the older Crucial/Micron M500 SSD? https://www.micron.com/~/media/documents/products/technical-note/solid-state-storage/tnfd23_m500_sma...

 

3) Does "Power on Hours" really show what the name implies? In my testing I noticed that rather than the amount of time the SSD has been kept powered on, it seems to show the "active time" of its controller. The more intensively the SSD is used, the faster is increases, as this graph shows. Note that the SSD has never been turned off since it was purchased. At about "real-time" 172 hours I performed some intensive read tests, which caused "Power On Hours" to increase faster.

MX500_real-time.png

 

4) This is a sort of follow-up to question 2. What is the expected short term Write Amplification Factor that one should expect with these drives under normal (light Windows desktop) usage? I found it tends to vary quite a lot, peaking to very high values, as the following graph shows (calculations with the formula given in the link in question 2. Values sampled every 30 minutes. The overall lifetime WAF is currently about 3.1x.

MX500-waf.png

 

 

 

 

More questions to follow...!

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