Multiple vs. Single M.2 NVMe SSD

Question

I plan to buy a Samsung 970 Plus 1 TB as storage drive and maybe an additional Samsung 970 Plus 240GB or 500GB for boot drive. I know SSDs do not function like HDDs. Nevertheless, I am wondering if there is any advantage to use multiple M.2 SSD (boot and storage drive separated) compared to a single M.2 SSD (boot and storage drive not separated).

Does two M.2 NVMe SSD have any advantage over a single M2. NVMe SSD?

If I use multiple M.2 SSD, will it better to have the faster M.2 SSD as boot drive or as storage drive?

An issue here is, that the M.2 SSD with smaller capacity has less speed than the SSD with higher capacity (240GB < 500 GB < 1 TB).

If I just use one M.2 SSD, does partition it affect its performance?

Can I freely partition a M.2 SSD with disk management? For example, can I just partition my 1 TB M.2 SSD to 188 GB and 812 GB? Or are there any things to consider like partition alignment that only allow me to partition my SSD to a specific size?

I have upgraded my PC for the first time, and I would appreciate your help!

Answer 1

TL;DR It depends, but generally two drives is faster.

Storage performance is generally measured by two metrics: throughput (aka sequential IO) and latency (random IO). Solid state drives are generally much (hundreds of times) faster than mechanical drives at random IO, and are generally at least as fast or faster at sequential IO.

For any given system, whether it's a single drive, separate drives for boot and data, or perhaps a RAID setup, more performant drives will (usually) result in a more performant system.

This generalization comes with a lot of caveats. It doesn't matter how fast your drives are if your application is not IO bottlenecked. It doesn't matter how fast your drives are if you're using a cheap RAID card that's IO bottlenecked. And in many cases, the increased performance may be on the order of a few percents (read: it takes 9.7 seconds to boot to desktop instead of 9.9).

To answer your questions specifically:

Does two M.2 NVMe SSD have any advantage over a single M2. NVMe SSD?

Probably.

If I use multiple M.2 SSD, will it better to have the faster M.2 SSD as boot drive or as storage drive?

This depends on what you mean by "boot drive" and "storage drive", and how you define "better". You probably won't be able to tell the difference.

If I just use one M.2 SSD, does partition it affect its performance?

No. ok, see below...

Can I freely partition a M.2 SSD with disk management? For example, can I just partition my 1 TB M.2 SSD to 188 GB and 812 GB? Or are there any things to consider like partition alignment that only allow me to partition my SSD to a specific size?

My understanding is that partition alignment only refers to a single-block-count-difference between mechanical drives and solid-state drives. If you're cloning your OS from a mechanical drive to the NVMe drive, then you may need to account for this. Otherwise, there should be no functional limitation (I believe there's a minimum partition size, but it is on the order of megabytes--you won't notice it).

Answer 2

If I use multiple M.2 SSD, will it better to have the faster M.2 SSD as boot drive or as storage drive?

This depends heavily of your usage. With my usage, I load many applications (from the boot drive since many install on the boot drive), and I like a fast boot. Then, my distribution :

• M.2 : boot drive, applications,
• HDD : my numerous files (photos) which are not used as heavily.
• SSD SATA : some heavy files (virtual instrument samples) which would be long to load from an HDD (typically 1GB loaded at the launch of its related application).

If you start your computer and its application once a while, and from it, deals many times with heavy files (genome sequences?), perhaps you may need an other distribution. But you may inspire yourself of my distribution and use the faster drive for the most used files.

Answer 3

In general you could argue larger SSDs offer advantages over smaller SSDs, everything else equal (same type of NAND chips for example, etc.).

• More NAND chips allows for more Parallelization. Controller can access multiple NAND chips simultaneously.
• Better longevity. NAND cells have limited p/e cycles, the smaller the SSD the quicker it will burn through them.
• Better wear leveling. More real-estate allows for more efficient wear leveling and will yield less 'write amplification' specially when SSDs are getting more full.
• If we assume 10% overprovisioning then even if say both a 250 GB and a 1 TB SSD are 'full', the the 1 TB model has 100 GB of 'wiggle-space' left, the 250GB model only 25 GB!

SSDs present themselves the same as conventional hard drives and can be treated the same way. So yes, you can partition them the same way too.