I agree Tesselator. But would rotational media apply to a SSD? Technically couldn't it fill up and never loose speed?
I don't have one so I haven't tested anything but using logic from my understanding of how they work, you wouldn't lose any speed at all from them being 99% full. You would however (maybe) kill the empty portion of the drive MUCH faster tho. If I understand it correctly, Wear-Leveling slash Dynamic wear-leveling uses the available free space and the incoming data to equally wear each of the physical blocks. This helps to reduce Block Retention time errors, Raw Bit Error Rates (RBER), and Uncorrectable Bit Error Rates. (UBER). Static data is not included in the available pool of wear-leveled blocks, leaving a portion of the drive with no wear and a portion of the drive (the free space) hyper-worn.
I read about a new feature called "Static Wear-Leveling" - which considers all physical blocks in the SSD, regardless of content, and maintains an even level of wear across the entire drive but I don't think it's been implemented into any currently available products yet. I could be wrong tho.
So with current SSDs you still want to keep them as empty as possible. Emptier they have a good UBER tho I forget exactly what it is. The manufacturer site will list it. Half full the UBER spec would logically be cut in half. And at 90% full the UBER would only be 10% of the manufacturer's listed specification.
There's also two kinds and I dunno what products use which. There are Multi-Level Cell (MLC) and Single-Level Cell (SLC) NAND devices. MLC has two bits of data stored per memory cell and four states [
erased (11), two thirds (10), one third (01) or programmed (00)] and needs logic level correction via EDC (Error Detection and Correction) whereas SLC is only 2 states and one data bit. EDC, Ware-leveling routines, and a number of other factors contribute to longevity or device durability but SLC fairs much better. The program and erase operations of SLC NAND Flash last 100,000 cycles - ten times longer than MLC NAND Flash, whose program and erase operations only last 10,000 cycles. After 10,000 and 100,000 cycles respectively, the reliability of NANDs program and erase operations are not guaranteed.
Because of it's more simplistic design Samsung is also claiming that their SLC based products will be (or are?) six times faster. Six time is massive and so is a 10x UBER, so make sure you select the right type. They're still too expensive for me so I've not looked into the situation at the product slash model level yet - meaning I dunno what's actually available nor who's using which technology.
