So after getting my RasPi3, and semi-impressed with the speed of the included Micro SD card, I decided to compare it with a few others I have...these are no generic crap cards rest assured.
To setup this test, all hardware other than the micro sd cards was identical, no changes in accessories or software. The micro sd cards were setup by downloading Noobs, installed and ran through the setup up to the same point, which was all updates installed and only admin user created.
I used the following command as my benchmark base:
Let me mention, the purpose of this test was to compare the speed of the RasPi3 bootup and reboot, with different micro sd cards. I have not run the numbers to compare speeds of moving small and large blocks, or sequential and non-sequential blocks from within the OS to a peripheral. That test would be useful, but only for those constantly moving files to or from attached storage and is not my use scenario as I was more interested in fastest boot times.
Code: Select all
dd if=/dev/zero of=/tmp/out bs=1M count=400
Below are the names, model numbers and links to the product page to the various micro sd cards I tested. Mainly I chose these models because I had them already for action cams, drones, DSLR, etc.
Boot times were clocked with a digital timer linked to a power source. When I flipped the switch, power activated to the RasPi3 and to the timer. The timer was manually stopped upon reaching the logon screen prompt.
Reboot times were achieved by first performing a clean boot to the OS, entering the password and waiting 3 minutes with no use just to ensure all services were running and all wireless signals connected. Then the restart button was pressed with linking the timer to the keyboard. When I pressed 'Enter' it initiated the timer and sent the command to RasPi3 to restart.
Now for the numbers!!!
I will list the SD Cards and results in this manner:
1) Micro SD Card Model, Speed-Class Rating, UHS Speed-Class Rating - Current Price on Amazon
Product Page URL
Bootup Time - Reboot Time - Transfer Size, Transfer Time, Transfer Speed (results from command provided).
1) 8gb, C6, U0 (included with Rasberry Pi) - $12.78
https://www.amazon.com/Raspberry-Pi-Pre ... ords=noobs
14 seconds - 16 seconds - 419 mb, 46.79 seconds, 9.0 mb/s
2) PNY 64gb, P-SDUX64U1-GES3, C10, U1 - $28.38
https://www.amazon.com/PNY-Professional ... DUX64U1-GE
19 seconds - 22 seconds - 419 mb, 17.96 seconds, 23.4 mb/s
3) Panasonic 16gb, C10, U3 - $53.49 (included w/ DJI Phantom drones)
https://www.amazon.com/Panasonic-16GB-m ... APanasonic
16 seconds - 27 seconds - 419 mb, 23.47 seconds, 17.9 mb/s
4) Sandisk 64gb, C10, U3 - $51.90
https://www.amazon.com/gp/product/B010N ... UTF8&psc=1
14 seconds - 16 seconds - 419 mb, 14.95 seconds, 28.1 mb/s
First thing to note: the cards are not relevantly 'faster' just because they are rated higher speeds. These speeds are calculated with including burst read/write speeds and each manufacturer may vary on how badly they exaggerate these numbers. Unfortunately, there is no "Department of Flash Memory Speed Standards" with soldiers on the ground to fine or arrest any such entities that claim their cards are U3 compliant...but only writing at 30mb/s...such as the Sandisk
Second thing: the burst speeds are not the most relevant with this use type. The most important thing to look at here is the 'Sustained read/write speeds'. Now in this test it was not so easy to show those numbers, nor was it the purpose of this article. The purpose was simply to find the fastest boot times. I will be running speed tests between these cards with large/small files and sequential/non-sequential files, to compare against what they claim it can do.
Last thing: as you can see from the tests above, the best overall card was the Sandisk...even though it was far slower than its claimed speeds. Tied with the micro sd card that came with the RasPi3 in boot & restart times, it does have a significantly higher read/write performance after it is running. Clearly the winner! But is it worth it? My opinion is no. Why will you spend $50 for a card that only performs nearly the same? If the purpose is storage, this is not the solution. Connecting an external drive to your wireless, or directly to the RasPi3 USB will be the right solution for local storage. If it is for a VM, or a database or service that requires everything to be local primary drive, then you may need to consider investing in a larger micro sd card.
To select the right card for your use, please ask yourself this question: do you want the RasPi3 to startup fast and be slower using it, or slower to startup and faster using it?
If your goal is pure boot times, find the card that has the highest burst speeds and typically these will be the higher capacity cards. But if you want better performance inside the OS, go with one that better sustained read/write speeds.
I hope this has been a helpful write-up to some and entertaining to others. I learn each day, I'm looking forward to hearing back from many of you and learning more from you.
Thank you and cheers!