Dirk Broer
06-01-2023, 12:18 AM
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....
-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....