Intel 480p as a Level 2 Cache

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davidst95
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Intel 480p as a Level 2 Cache

Post by davidst95 »

Hi, I have an Intel 460GB 480p and a 2TB Samsung 980 PRO NVMe drive. Does it make sense to use part of the Optane drive (maybe 64GB) as a Level 2 Cache? Will it slow down apps and games on the Samsung drive that uses higher queue depths? I thought it would increase speed and reduce the wear on the NVMe drive.

Thanks for any advice! I hope my questions make sense :-)

David
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Re: Intel 480p as a Level 2 Cache

Post by Support »

Do you mean Intel optane 900P? Samsung 980 PRO nvme ssd is much faster, and it doesn't make sense to use a slow drive as level-2 cache for a faster drive.
Hyperturtle
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Re: Intel 480p as a Level 2 Cache

Post by Hyperturtle »

Hello,

I have 5x 980 Pros in a RAID as well as two Optane 905ps in a raid -- both raids are used, in part, to cache other mechanical disk drive arrays I have.

I can suggest a few different scenarios, depending on what your ultimate goals are. Speed, endurance, capacity, lifetime, personal curiosity? Pick a few... then try the following.

I personally would recommend using the Optane to cache the 980 Pros for the purposes of endurance preservation, with no expectation of performance increase even with the small 4K file access. (You may achieve it--but do not *expect* it) You'll feel the data accessed by that, most likely, as being somewhat slower, but that may not be a problem depending on your needs if write endurance longevity is the goal.

You might have mechanical drives in your system as well--I have 8 mechanical HDs in the system I am speaking of, and my Optanes and 980Pros cache different hard drives with different purposes and goals in mind...

For performance improvement, you could make a RAID 0 volume from some or all of the available space on your 980 Pros, and partition it as desired to provide you with some space for super fast 980 Pro speed. Then perhaps create regular volumes on each 980 pro for Regular Stuff, or different cluster sizes, etc if you want to test tweaking like that--those singular volumes aren't all going to be lost if the RAID0 fails for some reason. If you have the capacity to spare, then use some of your system RAM to cache... any of that.

For the Optane, set aside perhaps 64GB of it for a "make my 980 pros live longer" cache, and use that as the L2 cache for a partition you want to use for whatever write heavy things you want to do. It will go slower than either 980 pro--but depending on the nature of your work, you may save a hit to the 980 Pro's endurance without slowing the whole thing down since you're only using a subset of the available space of the 980s to cache with the Optane.

If you don't actually have a specific goal in mind (such as a temp folder for say 7zip to use to write great big huge archives to and move back and forth from), then you may not see a lot of utility out of doing so, but if you have a good reason--you may see a benefit that translates into lifespan of the 980pros.

The Optane gives you options. in my experience with the Optanes, they often do indeed provide faster performance when caching the OS boot volume. I use Primocache to use about 64GB of my Optanes as an L2 cache for my boot volume, and I use 4GB of system ram for the L1 cache, and I achieve about a 99.7% hit rate after a little while. With this approach, The 980 pros, when not used to cache the OS or even store the OS, are spared the constant writes that the OS does all the time, and I can get away with using an SATA SSD for my boot volume and mostly get the speeds promised by the Optane technology without any of Intel's software driver hooha that doesn't support my computer anyway. I don't use defer write on the OS volume--I overclock, which means occasional blue screens, which means traumatic problems if defer writes fail because of my reckless behaviors. I do, however, use defer write caching on just about everything else.

The windows swap file also lives on my 980 Pros and the Optanes, and I can see they are heavily hit at times; Windows seems to greatly prefer the Optanes overall (and so I also use a small L1 cache on volumes the swap files live on, since some applications demand a swap file exists... and so I do the funny thing of using ram to cache the swap file to improve performance even further, even though some cool kids would laugh at me for doing that. Their ignorance is blissful, I guess!)

I agree with Support that it doesn't look like it'd help to use the 480GB Optane you have to generically cache your 980 Pros -- at least from a raw speed perspective. For endurnace, though, depending on what you want to achieve, it might be a good idea to reserve some of it for that purpose, but to also make a specific use volume or raid from your 980 Pros to set aside for the Optane to cache, so that you don't slow all of it down while still benefitting from the endurance preservation the Optane could provide for writes--depending on the stuff you are doing to cause those writes.

Considering all of this and the rough similarities between my system and yours, your best approach might not be a "do this specific thing", but rather a few different things to best achieve the results you want! And lastly-- you have my apologizes for the page long reply!
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Re: Intel 480p as a Level 2 Cache

Post by Support »

@Hyperturtle, thank you very much for sharing your experience! :thumbup:
Dichotomy
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Re: Intel 480p as a Level 2 Cache

Post by Dichotomy »

I have just paced Optane P1600X to cache my 1TB HP EX950 - and the resposivness improvement is very visible. Can't measure exact perfomance in Crystal Disk Mark due to the fact I cannot invent the way for PrimoCache to cache a test file taht CDM creates.

It's for short blocks small queue scenarios - 99,99% of home PC.
On the other hand linear read will not improve significantly and can even drop in some scenarios.
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