I finally got my Raspberry Pi which arrived today – after painful weeks of shipment. (Thanks to Svensk)
With great plans on my mind I decided to install my first Arch Linux ARM on my Rasp.
In this review I want to show you that choosing the right SD-card can make a major difference in boot-time and read performance, which is resulting in overall performance.
Let’s see what I’ve got!
Okay, I got these 5 cards of different classes which should be large enough for ArchLinux, but I didn’t know which performs best at all. Some people had very strange results, that Class2 cards were faster than higher classes.
The following SDs are available:
1. SanDisk Extreme III 8GB Class6
2. SanDisk Extreme 16GB Class10
3. SanDisk 4GB Class2
4. MemoryStar 16GB Class10
5. Transcend 32GB Class10
I expected that the "Extreme"-labeled SanDisks will perform better than the Class2 one.
Well, who doesn’t like benchmarks?
First Test: Transfer image to SDI transferred the ArchLinux image to all SD-cards.
Image: archlinux-hf-2012-09-18.img – Size: 1.98GB
Cardreader: Apple SDXC USB2.0 Cardreader
Less is better.
As I expected, at least one "Extreme"-labeled SD-card performed better than the non-labeled one.
It’s quite interesting, why 16GB isn’t as fast as the 8GB version – even though Class10 should be faster than Class6.
Weird stuff is going on … Let’s make some real world tests now.
Second Test: BootingTo get practical results I’ve decided to benchmark the bootup time.
In this test I took the time between power-on the Rasp and displaying shell prompt.
All five storage media were setup under the same condition.
Less is better
As you can see, the results aren’t related to the first transfer test.
If you compare the card’s classes, you will see that Class10 wins the race – closely followed by Class6.
In this case it’s essential to have the highest class available, no matter if you choose Class6 or Class10.
At this point the difference is quite insignificant between the both higher classes.
Third Test: Read performanceIn this last test I decided to take a look on read performance between all cards. Each card was tested several times to squeeze the last bit out of it. In addition I used the tool "hdparm" which returns the MB/s read rate of your card.
This benchmark was held on the Raspberry itself to measure read rates under real world conditions.
More is better.
This is what you pay for.
In this graphic you can see, that the higher class models read approx. twice as fast as low end models.
Surprisingly the no name MemoryStar card does very well at reading but writes 1MB/s less than the Extreme ones.
The conclusion of my short benchmark is, that different types of storage media can affect the performance of your Raspberry. You have to decide what you want and what you really need. Sometimes even low cost and no name products can be very good at reading.
If you plan a fast and realtime service, you should pick one of the "Ultra" or "Extreme" models for maximum performance and faster boot times. In all other cases I recommend taking the cheaper non-"Ultra"/"Extreme" models for your device.