@s12a wrote: @bogdan wrote: Could you please re-enable "Hot plug' option in BIOS for the SATA port the MX500 is connected t o? After posting this comment I will try to connect the SSD(s) back to the native Intel SATA controller and try this. About 3 days later, I can say that this did not fix either issue: About 24 hours after power cycling the SSD, 1 GiB FTL page write spikes started appearing, causing a slow rise in write amplification. Power on hours still increased slower than real-time (almost 72 hours have passed so far, while the count from SSD attributes has increased by less than 24 hours). I am starting to think that this (the anomalous WAF, at least) might be something related with the amount of time passed since the SSD was last power cycled, which could in part explain why not everybody might be seeing it. The red dashed line in the graph below shows when the SSD was power cycled and the "Hot Plug" option in BIOS enabled again on the native (Intel) SATA controller as suggested. The computer was never turned off over this period. The bright blue line shows Power On Hours Count (linear values on the right Y axis). The WAF since I last power cycled the SSD is currently about 3.09x, but it's 4.52x (and rising) since these spikes started appearing. If it wasn't for them, it would be about 1.25-1.35x, which means that the SSD at the current average Host Write rate would wear up at a rate roughly 2.5-3.0 times lower.
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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? 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_smart_attributes_calc_waf.pdf 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. 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. More questions to follow...!
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