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I need to add 4TB of fast storage to my (old) workstation. The workstation has SATA but no NVMe. The easy way is to RAID1 two 2TB SSDs, like the Samsung 860 EVO. I'm wondering how much faster it would be if I used four 1TB Samsung 970 EVO instead, with an ASUS HYPER M.2 x16 PCIe Expansion Card? Is it worth it?

Really depends on your use case

2x 2TB in RAID-1 will only give you 2TB, not 4. Putting them in RAID-0 would give 4TB and more speed, at expense of reliability.

It's impossible to make any judgment about how much speed is enough without knowing something about the workload. If a single SATA II drive can't provide enough speed, you're clearly beyond general desktop use.

RAID-1 of a pair of 2TB drives will give you only 2TB, not 4. Did you mean RAID-0?

If read throughput is your primary concern, the NVMe adapter approach will almost certainly win. For write-heavy workload, the sustained write performance of the SSDs will likely be your bottleneck whether you go with the SATA or NVMe approach; just take the sustained (NOT burst) write performance and multiply it by the number of devices (assuming you are doing RAID-0) to get a theoretical maximum throughput. (Real throughput will be less than theoretical due to overhead.)

RAIDing vanilla SSDs is a more mature (and therefore likely more stable) tech than that adapter you're looking at. Don't know how much that matters to you...

What are the specs on the system you want to put that card in? The system has to support PCIe bifurcation in order to see more than one drive on that card, and the card has to be in a full x16 slot (not a x16 slot that's electrically x4 or x8) to see all four drives. If you put it in a x16 slot it is only capable of x8, you will only see two drives. And only one drive is the slot is only capable of x4.

Also, you can only do RAID0 by default. To get RAID 1, 5 or 10, you need a system that supports Intel Virtual RAID on CPU (VROC). There is a cost for the key to enable to additional RAID level. And it also requires the use of Intel SSD's for those levels. I believe the RAID0 still requires a system that supports Intel VROC, but I think you can use any m.2 SSD for RAID0.

Thanks, guys. Yes, I meant RAID0.

The workload is read-intensive; the faster I can read the data, the faster the overall job will run.

My workstation has two full x16 slots but does not support bifurcation. So I'd have to use two 2TB Samsung 970 Evo, each in it's own x4 card, plugged into an x16 slot. Seems like a waste of PCIe lanes but they're not being used right now. It'll be slower than four 1TB NVMe drives but still faster than two SATA2 drives.

I'm surprised by the need for Intel VROC to get RAID on the NVMe drives. Why can't I just software raid them together?

branchingfactor wrote:

I'm surprised by the need for Intel VROC to get RAID on the NVMe drives. Why can't I just software raid them together?

You can - you won't be able to boot your system off such a volume, however for a secondary data volume this approach is totally fine.

So how much faster is 2 x 2TB 970 Evo M.2 vs 2 x 2TB 860 Evo Sata2, both in RAID0?

Is this accurate?
https://ssd.userbenchmark.com/Compare/S ... 8vsm430706

branchingfactor wrote:

So how much faster is 2 x 2TB 970 Evo M.2 vs 2 x 2TB 860 Evo Sata2, both in RAID0?

Is this accurate?
https://ssd.userbenchmark.com/Compare/S ... 8vsm430706

Based on experience, I would say yes. For just reading (large) files, I would say the NVMe setup would be 2-3 times faster, i.e. a file(s) loading in 20-30 seconds with the 970 will load in 1 minute with the 860. Actually, the initial latencies on the 970 should be much better too, but reading small files and gaining 0.1 sec doesn't seem to give you much real life sense of "faster" (unless you are doing something like loading 1 million 1K files in a batch, then you would notice it is SIGNIFICANTLY faster).

branchingfactor wrote:

I'm surprised by the need for Intel VROC to get RAID on the NVMe drives. Why can't I just software raid them together?

As Anton said, you can software RAID them in the OS and use any drives you want. Intel VROC is only available on systems with an X299 chipset (and presumably X399), anyway. And apparently there is a list of third-party SSD's that are supported, depending on which version of VROC the system has.

I also found this bit on the RAID0 support, so apparently it's hit or miss without the key:

An Intel® VROC HW Key is required to use RAID 0/1/5/10 for most SSDs. However, Intel VROC is also designed to provide RAID0 for Intel PCIe Gen3 x8 SSDs without requiring HW key. For instance: Intel® SSD DC P3608 Series. For any other regular x4 SSDs, without HW key, RAID0 might work, might not work. In short, an Intel VROC HW Key is required for official support for RAID0 with regular PCIe Gen3 x4 SSDs. Operating RAID0 in this situation is done at the risk of the user.