25% free space limit for SSDs.

[Easy_Gamer82]

Hi,

I have a 2TB SSD reserved for games and other potential backup situations. My understanding is that, in general, they don't recommend filling SSDs above 75% capacity, and leave 25% or more of free space. However, in this case, 25% of free space is around 460GB.

As such, is it really necessary to abide by this rule, especially if the SSD drive doesn't have any OS/system duties?

Any clarification would be appreciated.

Thank you

EDIT: The SSD is a Crucial MX500 2TB SATA drive.

[xSOSxHawkens]

The only real issue with using an SSD at full capacity is speed will be reduced, and that only applies mainly to drives that use SLC caching or similar, as the drives have NAND that runs at different effective speeds (mainly for writes), thus it tries to keep data stored in the slower nand for reads and tries to keep the lesser quantitiy faster nand open for cache use for writes. Running such a drive full prevents SLC caching and causes writes to suffer. That said, if the drive is a nicer one with a DRAM cache then the changes from being near capacity will be much lower.

My advice, fill it up, test it, and if it meets your needs you are fine to go. If its too slow then empty it out enough for the SLC caching to work right.

[Easy_Gamer82]

@xSOSxHawkens

That's good to know. Thank you for your reply.

[Carlsberg]

If the drive is filled to capacity it will still work fine because some overprovisioning is "built in" I believe, (around 7%), but as stated performance will be reduced. If the drive is just a storage drive then it may not produce any issues. Personally I work on 10% but have not filled any drives to that yet so cannot speak to its impact.

[nullable]

Yeah, the problem with those percentage recommendations is they're mostly made up, and repeated ad nauseam. I'd second xSOSxHawkens, about filling it up to test it and see for yourself if the fuss people kick up is worth your concern.

I personally don't worry about it on my SSDs though. On the off chance filling your drive up 80% full or 95% full or whatever did cripple it enough where you wanted to fix that, it's pretty easy to remove extra data. Filling up a 2TB drive probably means you'd have a few GBs you could remove if you had to. So you'd always have options from my point of view, so why worry about it?

[xSOSxHawkens]

EG, I run two different NVMe's. One is a 512GB Gen 4 that relies on SLC caching. When empty or below 50% it hits Gen4 speeds (ie 3-5GB/s), with it above 50 to around 80% the speeds drop to closer to NVMe Gen 3 (1-3GB/s) and with it above 90% capacity speeds drop to SATA comparable for most loads (~600-800MB/s) though it keeps up in smaller 4k reads. This drive uses a smaller Dram cache backed by SLC caching.

Comparably, I have a TLC 2TB Gen3 NVME with larger DRAM cache and no SLC caching. It stays more or less the same speed (~1.3-1.8GB/s) no matter how much I fill it up, all the way to full capacity with no noticable slow down.

[Bad 💀 Motha]

It depends on the SSD model; some have built-in Over-Provisioning; some do not have it enable and let the user do this and set that size.

I filled Samsung 850 and 860 and 970 all the time; they don't have any issues with slow-downs, even after many years of being wiped and filled again and again.

Crucial are junk SSD, I would never buy them.
I've yet to have any Samsung 850 or 860 fail even after many years of heavy usage.
Crucial has had way too many fails gone public for me to even try those out.
Only Samsung I had die were a couple customers who had a Samsung 840 series SSD back when those were new that had finally died; yea after like 10 years.

[Carlsberg]

引用自 Bad 💀 Motha：

It depends on the SSD model; some have built-in Over-Provisioning; some do not have it enable and let the user do this and set that size.

I filled Samsung 850 and 860 and 970 all the time; they don't have any issues with slow-downs, even after many years of being wiped and filled again and again.

Crucial are junk SSD, I would never buy them.
I've yet to have any Samsung 850 or 860 fail even after many years of heavy usage.
Crucial has had way too many fails gone public for me to even try those out.
Only Samsung I had die were a couple customers who had a Samsung 840 series SSD back when those were new that had finally died; yea after like 10 years.

Bought my first samsung SSD in 2011 right around the time they sold there HDD business to Seagate and proceeded to concentrate on the SSD business, all my SSD's since are samsung and I have never had one fail, the one I got in 2011 is still in use as an OS drive in a machine that pretty much runs 24/7.

[iceman1980]

That 25% is for if data blocks go bad. When you write to an SSD you can't actually write bit by bit, when the NAND flash is purged the entire byte data block must be purged as a result, when that block is purged eventually the blocks will begin to fail a long time down the road the 25% ontop is to mainly protect your data that could be lost from a datablock loss.

That is what the 25% is for, when it's provisioned. It's simply a data protection measure.

[Bad 💀 Motha]

Well I've had alot of luck with Samsung SSDs and until I see otherwise, they've been by far the most reliable brand of SSDs I've ever used; and I've used many brands of them ever since SSDs reached the consumer market in SATA form.

[Illusion of Progress]

引用自 Bad 💀 Motha：

Crucial are junk SSD, I would never buy them.
I've yet to have any Samsung 850 or 860 fail even after many years of heavy usage.
Crucial has had way too many fails gone public for me to even try those out.

First time I've heard someone say that of Crucial as usually they're known to be solid as far as I'm aware, in both SSDs and memory. They're usually not the first choice for performance seekers but they usually have solid stuff for the price in my experience.

The only SSD brand that stands out to me as having had a really bad reputation was OCZ with their Vertex SSDs and that was in the early 2010s.

[Andrius227]

It only matters for OS drive anyway. For extra drives it does not matter and you can fill them up as much as you want. At least i run my 4 dedicated steam ssd's at ~95-99% and never see any slowdowns or anything.

[Guydodge]

ive always left 10% open seems to work fine.

[Easy_Gamer82]

All great answers. Thank you, all.