Question about overprovisioning an SSD

[southleft]

If I overprovision, say, 25% of a 1TB Intel 660p will that reserved capacity be used as SLC cache?

Many new NVMe SSDs use a variable portion of the drive's capacity as an SLC cache to help maintain high Write speed when transferring sustained large amounts of data. As the drive fills up the available cache size diminishes, and the speed of sustained Writes slows dramatically when the cache is saturated. So, if I settle for 750GB of usable capacity on the drive, will the unused/unallocated 250GB be employed by the drive controller to maintain high Write speed? Or, does this extra overprovisioning only affect endurance?

 

[UsandThem]

The drive will automatically treat free space as over-provisioning, so there's no need to manually set one anymore. It helps a little with speed, but is mostly used for endurance reasons.

As far as the SLC question, no. The drives come with a fixed portion, and once you fill the static SLCit all the way, performance will drop a bit. That said, you must not constantly write extremely large files (or move them), or you wouldn't have bought the 660P in the first place.

Here's the review at Tom's where they expand on the SLC cache dynamic feature (outside of the fixed SLC cache I mentioned above):

https://www.tomshardware.com/reviews/intel-ssd-660p-qlc-nvme,5719.html

 

[southleft]

OK, let me use different words here. I'm asking about Intel's Intelligent Dynamic SLC-Caching, which uses a pool of fast SLC flash to boost performance for incoming write data. The question is whether or not this caching method will include/use/employ/access unallocated capacity in the Dynamic SLC-Caching.
Example: 1TB Intel 660p
Drive is partitioned as 750GB boot partition.
Remaining 250GB remains unallocated space; not formatted, no drive letter, nothing, just unused capacity.
Does Dynamic SLC-Caching "see" the unallocated capacity and use it for dynamic caching?
Can I be any clearer?
Thanks.

 

[UsandThem]

OK, let me use different words here. I'm asking about Intel's Intelligent Dynamic SLC-Caching, which uses a pool of fast SLC flash to boost performance for incoming write data. The question is whether or not this caching method will include/use/employ/access unallocated capacity in the Dynamic SLC-Caching.
Example: 1TB Intel 660p
Drive is partitioned as 750GB boot partition.
Remaining 250GB remains unallocated space; not formatted, no drive letter, nothing, just unused capacity.
Does Dynamic SLC-Caching "see" the unallocated capacity and use it for dynamic caching?
Can I be any clearer?
Thanks.

The link I gave you above talks about that, and shows performance once the SLC cache is exhausted, and it starts using dynamic cache pool.

You do not need to manually set a manual over-provision anymore. It does not matter if the free space is formatted, or if it is unallocated space. Any free space on your drive will be treated as one. From the review above:

In other words, the cache shrinks as you fill up the drive but expands as you delete items.

Do you constantly write or move 12 GB+ files on a routine basis? If so, you likely should have bought a NVMe drive with TLC NAND and not one with QLC. However, if you use your drive like 90% of users typically do (programs, games, small-to-medium files), you do not need to do anything and can just simply use the drive without worry.

 

[southleft]

Can anyone answer my actual question, please?

 

[Maxima1]

Can anyone answer my actual question, please?

The 1TB model varies from 12GB to 140GB depending on filled capacity. QLC doesn't convert 1:1 with SLC, so you can't have the rest of the space all as SLC. The drop off is quite steep, though they say they couldn't fully capture the dynamics of the cache.

https://www.anandtech.com/show/13078/the-intel-ssd-660p-ssd-review-qlc-nand-arrives

 

[UsandThem]

Can anyone answer my actual question, please?

Wow, don't sound so appreciative with me trying to help you out by answering your question.

I'll remember it the next time you need some help.

 

[southleft]

Thank you, but that does not answer my question any more than the previous posts.

 

[UsandThem]

Thank you, but that does not answer my question any more than the previous posts.

I think you already have your answer in your mind, and it doesn't matter what anyone really has to say.

So go ahead and create a 25% over-provision on your drive, and enjoy! With that, I'm done spending any more time in this thread.

 

[Maxima1]

Thank you, but that does not answer my question any more than the previous posts.

Yes it does. The chart shows that if you have =>75% used capacity, you'll have only 12GB of SLC available. If you have 50% unused, then you have 75GB SLC cache available. And so on.

 

[southleft]

I don't think you understand the question. I read the reviews before ever posing the question. The reviews do not discuss the possibly of using additional unallocated space for caching for the purpose of maintaining Write speed.

As the drive space fills up, the amount of space used for SLC-caching diminishes. But, wait, if the main partition is only using 750GB total on a 1TB drive, then, hey - look, there's a bunch of totally unallocated space - almost 250GB - how 'bout allocating that totally unallocated space to maintain a large SLC-cache? Can the Intel Dynamic SLC-caching software do that? Yes or no?

 

[Maxima1]

I don't think you understand the question. I read the reviews before ever posing the question. The reviews do not discuss the possibly of using additional unallocated space for caching for the purpose of maintaining Write speed.

As the drive space fills up, the amount of space used for SLC-caching diminishes. But, wait, if the main partition is only using 750GB total on a 1TB drive, then, hey - look, there's a bunch of totally unallocated space - almost 250GB - how 'bout allocating that totally unallocated space to maintain a large SLC-cache? Can the Intel Dynamic SLC-caching software do that? Yes or no?

It's pointless to do that, though. It's not necessary.

Anyway, I'm like 99.99999% confident that non-user space (i.e. unallocated) will get used to boost performance. But again, it's not necessary to leave out of user space.

https://www.techspot.com/news/52835...-need-for-trim-overprovisioning-and-more.html

"The SSD uses non-user space in the flash memory (over provisioning or OP) to improve performance and longevity of the SSD. In addition, any user space not consumed by the user becomes what we call dynamic over provisioning – dynamic because it changes as the amount of stored data changes. "