RPi Power Consumption
March 11, 2019
Raspberry Pi Mass Storage Power Consumption
As described in my original twitter thread…
How do mass storage devices impact power consumption of Raspberry Pi?
I wanted an idea of UPS runtime, so I scripted a benchmark to run at boot:
- write 100x 128MB files
- flush cache w/1GB file
- read 100x 128MB files
- shutdown
Measure duration, energy consumed, etc
Testbed
- Raspberry Pi 3B+
- ATP aMLC 4GB microSD
- Raspbian Stretch Lite 2018-11
- TalentCell 12V6Ah/5V12Ah DC UPS
- Drok USB multimeter
- StarTech USB-SATA cable (connected as needed)
Devices Tested
- Baseline: Raspbian idling, no mass storage
- USB microSD: Samsung Pro Endurance 32GB + Kingston adapter
- USB flash: SanDisk Ultra Fit 32GB
- SATA 2.5 HDD: Seagate BarraCuda 1TB
- SATA 2.5 SSD: SanDisk SSD Plus 480GB
Results
- Baseline (idle): 12m 47s, 431 mWh
- USB microSD: 36m 24s, 1475 mWh
- USB flash: 21m 39s, 1115 mWh
- SATA 2.5 HDD: 14m 49s, 1376 mWh
- SATA 2.5 SSD: 12m 47s, 840 mWh
Conclusion
- SSD provides significant improvement to efficiency & speed. Best choice when budget and physical space allow.
- For lower budgets or compact form factor, USB thumbdrive is the best compromise.
- SD card is slowest and least efficient, avoid when possible.
Metrics
Baseline (idle)
- Duration: 770 sec
- Energy: 431 mWh
- Mean xfer (r/w): 10.9 / 18.06 MB/s
- Mean freq: 610 MHz
- Mean temp: 47.6 C
USB microSD
- Duration: 2000 sec
- Energy: 1475 mWh
- Mean freq: 620 MHz
- Mean temp: 47.6 C
- Mean xfer (r/w): 18.1 / 10.9 MB/s
USB flash
- Duration: 1280 sec
- Energy: 1115 mWh
- Mean freq: 636 MHz
- Mean temp: 48.3 C
- Mean xfer (r/w): 36.8 / 15.9 MB/s
SATA 2.5 HDD
- Duration: 900 sec
- Energy: 1376 mWh
- Mean freq: 636 MHz
- Mean temp: 45.7 C
- Mean xfer (r/w): 35.2 / 28.2 MB/s
SATA 2.5 SSD
- Duration: 770 sec
- Energy: 840 mWh
- Mean freq: 704 MHz
- Mean temp: 46.9 C
- Mean xfer (r/w): 37.6 / 35.0 MB/s