PrimoCache performance on PCIe 4.0 vs 3.0? Slot 1 vs 2?

FAQ, getting help, user experience about PrimoCache
Post Reply
Toyzrme
Level 1
Level 1
Posts: 3
Joined: Thu Mar 25, 2021 7:59 pm

PrimoCache performance on PCIe 4.0 vs 3.0? Slot 1 vs 2?

Post by Toyzrme »

Has anyone tested performance of using L2 cache on PCIe 4.0 NVMe vs 3.0? (on a PCIe 4.0 MoBo, of course)

Or on the first NVMe slot vs. second? (i.e. CPU direct PCIe lanes vs. via chipset, assuming that's connected via PCIe 4.0)

Just curious whether it's worth:
1) Paying for PCIe 4.0 NVMe drive (like 980 Pro)
2) Using the 2nd NVMe slot as the boot drive, so that the L2 cache is closest to the CPU for less latency

Any thoughts? Would I even notice the differences?

System-to-be: AMD 5950x 16c, X570 MoBo, 128GB, 2x NVMe (OS + cache), RTX3080, 35TB RAID6 (5x HDD), 4K display
Uses: Video and image editing
xinwei
Support Team
Support Team
Posts: 28
Joined: Mon Jan 25, 2021 8:35 am

Re: PrimoCache performance on PCIe 4.0 vs 3.0? Slot 1 vs 2?

Post by xinwei »

It depends on the SSD itself. Currently most nvme SSDs support PCIe 3.0x4 which speed limits to 4GB/s in theory. Some SSDs now support PCIe 4.0, and their speed beyond 4GB/s.
Babel17
Level 5
Level 5
Posts: 40
Joined: Tue Nov 03, 2015 3:41 pm

Re: PrimoCache performance on PCIe 4.0 vs 3.0? Slot 1 vs 2?

Post by Babel17 »

I think that latency could be among the most important concerns with a L2 cache, and IIRC all SSD are excellent in that regard. I have a PCIe 4.0 NVMe drive on a X570 mobo, with an AMD 5900X which it was inserted next to. It is pretty much tied for being the fastest drive around, a one TB WD Black SN850. For moving data around it's wicked fast, but clicking on a file on it vs. clicking on a file on my five year old Mushkin Striker SATA SSD is about the same.

So if using L2 set to read only, which is what I have the L2 cache on my older NVMe drive which sits in the other NVMe slot in my ASUS mobo, then you should be fine with whatever you go with. Though these drives are supposed to last a long time, so it might be worth spending a few extra dollars for something that will be used later on in other PC builds that you have.

If you are most concerned about gaming, then benchmarks show that level loads are excellent no matter what SSD you have. The most expensive drives can sort of justify their expense if you are looking at long and brutal drive writes, ones that exhaust their internal ram cache, and SLC pseudo cache. Then the controller has to work its magic, as do the underlying cells of the drive.

Edit: Sorry, you spoke of video editing. Btw, I too have a RTX 3080, and a 4K TV/monitor. I guess if video editing causes you to wait on huge files of raw video streaming from drive to drive as they are edited, and transcoded, you might want a crazy fast NVMe drive. Are you getting a pre-built? It's nearly the only way to get the parts you mention. That's what I did, from Cyberpower PC.
Toyzrme
Level 1
Level 1
Posts: 3
Joined: Thu Mar 25, 2021 7:59 pm

Re: PrimoCache performance on PCIe 4.0 vs 3.0? Slot 1 vs 2?

Post by Toyzrme »

Thanks - there are so many benchmarks, statistics, and opinions out there, it's hard to get/formulate a clear, definitive answer (and yes, I know it depends on a lot of parameters).

Sounds like we'd get along - I have a 50" 3D 4k TV as my monitor. Building my own system - still waiting for my 5950x to come in (until then, running a 3600 on my x570 MoBo). I have a GTX 1080, which hopes to someday grow up to be a 3080, if/when they return to retail prices (hey, stop laughing!!!). The MoBo is filled with 128GB of 3600 RAM, and I decided to go with a 1TB 980 Pro for boot, and 2TB 980 Pro for cache and/or fast source storage, depending on testing (Puget DaVinci benchmarks). Was torn on the SN850 ...

The part that uses a lot of file seeking is scrubbing through the footage - so you're jumping around in big files, pulling a few frames, then jumping again. That's why I'm leaning towards just putting all 2TB in front of my 32TB RAID6 HDD set, and let Primocache figure it out (probably no L1?). Then put a modest RAM cache (L1) in front of the boot drive (10-20GB).

May last build is 5 years old, with a 512GB Samsung 951 NVMe - 1,800/1,300 MB/s, and $350. Wow, huh? LOL 250TB written without using it very heavily.
Post Reply