SSDs, how fast is fast enough?

[Dirk Broer]

When we buy hard disks, whether they are HDDs or SSDs, we want them to be fast and have as much GBs as possible,
-for the money we spend. But how fast is fast enough, and what about your lecky bill?

If and when you have a crunching farm -and I would swear I didn't have one, until a quick look in BOINC Tasks learned
me of more than 20 attached devices..- that lecky bill becomes more important.

If and when the majority of your crunchers flees the premises when someone barges in, shouting "ARMed police!",
the Watts needed to read/write are very important indeed. What's the point in having a system running that only needs
a 5V PSU when the attached SSD eats more than 5 Watts from the wall, thereby hampering the functioning of the said
ARM-cruncher because the skimpy standard 5V PSU can't cope with the demand?

Now that 5 Watt for an SSD may seem much, but your latest Intel and/or AMD x86-64 system that supports
PCIe 5.0 x4 M.2 NVMe SSDs can be used with SSDs running even more Watts -and thereby running so hot they really
need active cooling. Sounds familiar?

The PCIe 5.0 x4 I looked up even used between 10 and 11 Watts for read/write tasks, their read/write speeds being
between 9.500MB/s and 12.400MB/s.

The PCIe 4.0 x4 I looked up used between 0.08 and 10.9 Watts for read/write tasks, their read/write speeds being
between 1.000MB/s and 7.500MB/s.

The PCIe 3.0 x4 I looked up used between 0.075 and 8 Watts for read/write tasks, their read/write speeds being
between 515MB/s and 3.500MB/s.

Note that both the PCIe 4.0 x4 and PCIe 3.0 x4 see a factor hundred in difference between the cheapest running
system and the most expensive ones.

Now the ARM systems I have generally can't be used with a direct attached M.2 SSD (except for the Odroid-M1
and the Jetson Xavier NX) and when you attach a M.2 SSD via USB 3.0, you are effectively at SATA-600 data
transfer speeds, so that's a big NO. But even those SATA-600 SSDs come in different performance classes!

The SATA-600 devices I looked up used between 0.002 and 9 Watts for read/write tasks, their read/write speeds
being between 140MB/s and 7.400MB/s.

That's almost a factor 10.000 in Watts read/write difference we see here....

published in an mobile/cell phone friendly format, I hope....

[Dirk Broer]

Let's start with the ultra-fast Watt burners:

The fastest sequential readers (12.400MB/s) and writers (11.800MB/s) are the 2 and 4 TB versions of the Crucial T700 series.
Neither their random read/write speeds, nor their energy consumption figures were given, but I found the random speeds
at this review by Shane Downing at Tom's hardware: Crucial T700 SSD Review: The Temporary King. The fastest consumer SSD you can buy is here.

Performance comes with a price however: the 4TB models do around 700 Euro's over here -the ones with heatsink going over 700, the ones without staying just under the 700 barrier. Makes you wonder about their name, T700 series....

PCIe 5.0 x4 can be done cheaper though: the 1TB models of the Corsair MP700 are around 190 Euro's and still reach speeds as
Seq. read: 9.500MB/s, Seq. write: 8.500MB/s, random read: 1.300.000 IOPS, random write: 1.600.000 IOPS and taking 10 Watt to do so.

40 Euro's more and you have the 1TB Crucial T700, flirting with its 11.700MB/s Seq. read and 9.500MB/s Seq. write speeds.....

BTW: I've spotted the first 60mm fan-equipped M.2 cooler on AliExpress