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JPWhite
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UHS-3 Micro SD Card. Can the Pi take advantage of the speed

Tue May 31, 2016 1:38 pm

I noticed that some new 'Pro' Micro SD cards offer 90MB/s read speeds vs the 45MB/s speed of other class 10 devices. They are Class 10 UHS-3.

Can the SD Card controller on the Pi take advantage of the extra speed?

I have my second Pi on order along with one of these faster cards. What benchmark for the Pi evaluates the speed of the SD card? When I get it I can post results here.
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fruitoftheloom
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Re: UHS-3 Micro SD Card. Can the Pi take advantage of the sp

Tue May 31, 2016 2:08 pm

JPWhite wrote:I noticed that some new 'Pro' Micro SD cards offer 90MB/s read speeds vs the 45MB/s speed of other class 10 devices. They are Class 10 UHS-3.

Can the SD Card controller on the Pi take advantage of the extra speed?

I have my second Pi on order along with one of these faster cards. What benchmark for the Pi evaluates the speed of the SD card? When I get it I can post results here.

http://www.pidramble.com/wiki/benchmarks/microsd-cards
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JPWhite
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Re: UHS-3 Micro SD Card. Can the Pi take advantage of the sp

Tue May 31, 2016 3:36 pm

fruitoftheloom wrote:
JPWhite wrote:I noticed that some new 'Pro' Micro SD cards offer 90MB/s read speeds vs the 45MB/s speed of other class 10 devices. They are Class 10 UHS-3.

Can the SD Card controller on the Pi take advantage of the extra speed?

I have my second Pi on order along with one of these faster cards. What benchmark for the Pi evaluates the speed of the SD card? When I get it I can post results here.

http://www.pidramble.com/wiki/benchmarks/microsd-cards
Thanks for the link!!

I ordered the Samsung Pro 16GB which is up near the top of the list. Be interesting to see how fast the RPi goes with this memory. It's only $13.99 at the moment. http://amzn.to/1Pg2y9S

Awesome that you can overclock the SD Card reader for even more throughput.
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Re: UHS-3 Micro SD Card. Can the Pi take advantage of the sp

Tue May 31, 2016 4:16 pm

This is the one that I was using on my Pi 3, before I used the 8gb Noobs card for the Bootloader and a 300gb hard drive for Raspbian.

She flew as fast as a SSD runs. I now have that card in my Matricom G-Box Q2 as extra storage. It flies quickly on that box also.

It was $50 when I bought the card on Newegg from a vendor. They are out of them now. Now you can get a decent 120gb SSD for $73.36. Samsung's 850 evo 3-D Vertical. I have not had a chance to run it on my Pi3 yet. I can say that the 3-D Vertical SSD's are a huge step forward, before you start getting into the M.2's, which we will have to wait and see if Raspberry and Adafruit will support them.

"Samsung 128GB EVO Micro SDXC up to 48MB/s with Adapter (MB-MP128DA/AM)"

Model

Brand SAMSUNG
Series EVO
Model MB-MP128DA/AM
Type microSDXC
Details

Capacity 128GB
Speed Class Rating UHS-I / Class 10
Read Speed Up to 48MB/s
Write Speed Up to 25MB/s
Features
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thecommentator
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Re: UHS-3 Micro SD Card. Can the Pi take advantage of the sp

Wed Jun 15, 2016 6:02 pm

UHS-I and UHS-II refer to bus types, while U1 and U3 are speed ratings. Does the Pi support 1.8V SD operation required to take advantage of a UHS-I card?

From https://en.wikipedia.org/wiki/Secure_Digital#UHS

"Use of UHS-I requires that the host device command the card to drop from 3.3-volt to 1.8-volt operation over the I/O interface pins and select the four-bit transfer mode, while UHS-II requires 0.4-volt operation."

I ran into the voltage issue while testing SD cards on a non-Pi Linux platform. Another thing I noticed, which might be affecting the Pi community, is that when I reformat an SDXC card from exFAT to FAT32, I continue to see fast read speeds (~50MB/s) that reflect 1.8V operation, but write speeds suffer in a strange way. Immediately after the reformat, write speed is reasonable, but drops off after just a few dd test. In MB/s I saw 37, 32, 18, 13, 17, and then it remains in the teens.

I'm trying to find out if there is some magic that means SDXC performs correctly only as exFAT.

Romonga
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Re: UHS-3 Micro SD Card. Can the Pi take advantage of the sp

Wed Jun 15, 2016 6:05 pm

The speed of the memory card will drastically effect the performance of the Pi. Many cards list speeds, however this is a misleading bit of info. A lot of it has to do with the block allocation size. The Pi uses a 4K block size, as such you need to find a card that can handle this well.

I use a SANDISK 128 Gig Card, with a 4k Block speed about 5 meg per sec.
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HawaiianPi
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Re: UHS-3 Micro SD Card. Can the Pi take advantage of the sp

Thu Jun 16, 2016 8:21 am

thecommentator wrote:UHS-I and UHS-II refer to bus types, while U1 and U3 are speed ratings. Does the Pi support 1.8V SD operation required to take advantage of a UHS-I card?

From https://en.wikipedia.org/wiki/Secure_Digital#UHS

"Use of UHS-I requires that the host device command the card to drop from 3.3-volt to 1.8-volt operation over the I/O interface pins and select the four-bit transfer mode, while UHS-II requires 0.4-volt operation."

I ran into the voltage issue while testing SD cards on a non-Pi Linux platform. Another thing I noticed, which might be affecting the Pi community, is that when I reformat an SDXC card from exFAT to FAT32, I continue to see fast read speeds (~50MB/s) that reflect 1.8V operation, but write speeds suffer in a strange way. Immediately after the reformat, write speed is reasonable, but drops off after just a few dd test. In MB/s I saw 37, 32, 18, 13, 17, and then it remains in the teens.

I'm trying to find out if there is some magic that means SDXC performs correctly only as exFAT.
The Pi does not support 1.8V or U1 writes, but faster cards still make a very noticeable difference.

The problem is most cards are optimized for sequential I/O, while computers often perform non-sequential I/O. Look at the benchmark link above for the cards with the faster random read/write. Those will be the best performing cards on the Pi.

The best bang for the buck is probably the Samsung EVO+, which is pretty affordable and outperforms many much more expensive cards in random reads, and especially random writes. I have one of those, and the Pro as well, and I can't tell the difference, even though the Pro is twice the price and is supposed to be much faster at writes (which I don't think the Pi can take advantage of). So look for sales on the Samsung EVO+ and snatch one up.

Also note that larger cards often have faster write speeds than smaller ones (with 32GB often being the tipping point). So if you want the fastest performance, get at least a 32GB card.
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AikonCWD
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Re: UHS-3 Micro SD Card. Can the Pi take advantage of the sp

Thu Jun 16, 2016 9:35 am

To get more speed while reading or writting into microSD, you must overclock the mmc driver of your raspberry. More info here:

https://github.com/aikoncwd/rpi-benchmark
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Omicron777
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Re: UHS-3 Micro SD Card. Can the Pi take advantage of the speed

Thu Jan 04, 2018 6:16 pm

My 1st Rpi3, I used an old 16-Gb msdhc card just sitting around & it worked; then I purchased a Samsung 32-Gb msdhc uhs-1 thinking 'it's been about two years, this card should work...'

Not a chance; apparently my old mSD card was a 16-Gb SanDisk uhs-3. The Samsung 32-Gb uhs-1 booted and installed Kali Linux, just at an ungodly pace. When I went to install Kali Linux Full like my other RPi3, it made it about 5m before freezing. Lesson learned though.

Very glad I found this page & see that I can get even higher speed via overclock too!

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