MicroSD Card performance
Yesterday I changed my “old” micro SD card (SanDisk Extreme, very good too) to a new one SanDisk Extreme “Pro” 32GB.
Really good the change, looks like I turn on the “turbo”.
Only a Tip, the SDCard quality and speeds is really an important point for performance.
Good to know. I went for the cheaper Samsung EVO cards and got one of their PRO’s. I’ll do a benchmark sometime. I’m wondering what the impacts of different cards are regarding:
- APM - Low impact I guess it should all be in RAM anyway (besides log writes) as long as they support Pixhawk at least (small enough to fit in the Pi memory).
- FPV stream & record (like a Mobius but using PiCam and the same SD storage) - Guess high impact for recording, low impact if just streaming.
- Comparison of “real world” SD card performance against a modern USB2 flash drive (in theory up to the maxium USB2 spec of 60MB/sec).
I didn’t find the exact specification of the Raspberry PI 2 SD card reader, just that it is the same as the Pi 1:
But I guess it is UHS compatible. Well not so good then, because my Samsung EVO claims class 10 UHS-I, which I presume “I” means ONE so only 10MB/sec even though it claims 48MB/s transfer on the manufacturer’s web site:
What UHS speed index does your card have/claim?
It’ll be interesting when the ODroid is supported (good that Emlid are working on that), with USB3 it will provide a solution for heavy users.
Read Up to 95MB/s ; Write Up to 90MB/s
for 26us$, not bad…
If you actually got those speeds on the Pi (i.e. via benchmark) it would be even better (I guess you are quoting the specification). It’s just a little bit more expensive per GB for twice the speed.
What I’m wondering is whether the Pi can really deliver more than 60MB/s via the SD card reader. Because then USB2 storage is not worth bothering with (except on the ODroid with USB3). The specification says UHS is capable up to over 300MB/s, so it’s possible you’re really getting 90MB/s+ on the Pi.
I’ll check it out, thanks!