SSD capacity write speed vs. retrieve speed

[ZJKmusic]

I run multiple external hard drives off of my iMac, including 2 1TB thunderbolt SSDs.  

 

Both of these hard drive are around capacity (about 90%).  I have been reading that when SSD go over around 70% they begin to lose their speed.  However, everything I've found that talks about this or provides some detailed information refers specifically to the write speed.  I use both of these for streaming audio samples for music projects.  So they have never been at anything other than 90% capacity but also they never have any information written to them either.  So I only ever access the data that's stored and I haven't stored any additional data on them since my initial load up of all of the audio files to be streamed.  

 

My question:  Does the recommended 70% capacity limit apply to write speeds only (i.e. retrieval speeds remain unaffected) or would this affect streaming data off of these drives and I have been operating under less than ideal speeds this entire time?  

[KarathKasun]

Read speeds will not suffer, writes take a nosedive though.  Also, dont do much writing with the SSD at 90% capacity.  This can significantly reduce the drives lifespan.

[Electronics Wizardy]

A lot of thie speed loss depends on the exact ssd adn load load.

 

Having them full won't kill the drive and speed, its mainly that it has to do a lot more data shuffling and hurts endurance a bit when full, but this mainly applys when trim is enabled.

 

For reads only, you can fill it all the way up.

 

Also the % isn't a great measurement with bigger drives, so a 1tb drive with 90% used is fine as you still have 100gb free

[seagate_surfer]

Hello ZJKmusic,

 

There are several different factors that affect the performance of one drive including the motherboard controller, drivers, firmware, capacity... But reading is not one of them, browsing the internet, playing your videos, music, opening the pictures, is not writing that's reading and it won't affect your drive like moving files from one folder to another, copying, using it as a backup between other actions do. That's why you see people posting on the internet about speeds but never complaining about reading, because reading usually is not impacted when IOPS problems occur.