Is it the same card reader in all boards?

How is it connected to the CPU?

Trying to determine which microSD cards to install so that the card isn't the bottleneck.

Why on earth do you need performance on the card reader?

Yes they are connected to the CPU and the CPU differs. No there is no performance to talk about, a MB/s at most.

Why on earth do you need performance on the card reader?

Yes they are connected to the CPU and the CPU differs. No there is no performance to talk about, a MB/s at most.

To not wastefully overspec the card I install. Shipping my router to be installed at another, not easily accessed location.. Choosing between a U1 and U3 uSD card right now. If the card readers are fast enough, I'll look for a V60 or V90 card, but I suspect it is not that fast.

The 'Container' feature that will hopefully return was my first thought.

There are other features that will use fast transfer speeds already..

If reliability is needed other than write/read speed (not a must) I will go for industrial grade uSD.

Mikrotik Support gave me an answer..

RB760iGS and RB750Gr3:
Upload to microSD ~51.8Mb/s
Download from microSD ~54.7Mb/s

CCR1009-8G-1S-1S+
Upload to microSD: ~2.8Mb/s
Download from microSD: ~1.9Mb/s

The speed difference between the two shocked me.

Some CPUs used in routers have dedicated pins for SDIO, ie they have hardware support for things like faster transfers using multiple bits/clock and can offload some of the workload (CRC).
In other models SD is connected just over generic SPI bus, so it's much slower.
Sadly there is no official information about this on hardware pages or device datasheets. With upcoming container availability on all platforms it would be good to have these numbers measured and listed by Mikrotik so users know what to expect...

In other models SD is connected just over generic SPI bus, so it's much slower.
Sadly there is no official information about this on hardware pages or device datasheets. With upcoming container availability on all platforms it would be good to have these numbers measured and listed by Mikrotik so users know what to expect...

Yes, that is what I was looking for when I created the thread.

Otherwise, I wonder why SPI and not the USB interface on the CPU, even that would have made significant gains.. Oh well.. I do have my answer though..

Speaking of which, I wonder if a USB-OTG card reader would work.. Startech's MSDREADU2OTG maybe.. Humm..

There are some weird choices on some Mikrotik boards, like pretty much every SoC CPU nowadays have USB host support... but sometimes they just choose not to make it available.
Usually when I mentioned, I heard "every $0.1 matters for low cost HW" argument, but why not at least have PCB header available? Some of these SoCs even have USB 3.0...
But overall if board have USB, likely any mass storage device will work. There is no difference between common SD card reader and USB flash drive, some of them actually have SD card in them... if you wanted even higher performance (maybe on USB 3.0 board) M.2 SSD in USB enclosure could be much faster than internal flash or anything else.

There are some weird choices on some Mikrotik boards, like pretty much every SoC CPU nowadays have USB host support... but sometimes they just choose not to make it available.
Usually when I mentioned, I heard "every $0.1 matters for low cost HW" argument, but why not at least have PCB header available? Some of these SoCs even have USB 3.0...
But overall if board have USB, likely any mass storage device will work. There is no difference between common SD card reader and USB flash drive, some of them actually have SD card in them... if you wanted even higher performance (maybe on USB 3.0 board) M.2 SSD in USB enclosure could be much faster than internal flash or anything else.

Indeed.

I'm thinking specifically of my CCR1036 router right now, which has a USB 2.0 OTG port and currently has 4GB RAM, but expandable, so putting in 'good' storage would be important for containers.. At least with SD cards I can choose the memory used.

My CCR1009 is getting sent offsite, 2GB RAM should still be sufficient.

Plus a OTG SD card reader should be self-supporting, it should be able to sit just in the port, wouldn't need to support a drive's weight.

I remember with my RB2011 the CPU would go 100% whenever writing to the internal memory...

"Usually when I mentioned, I heard "every $0.1 matters for low cost HW" argument"

But they included a smart-card reader in some models which has never worked and never will.. So sometimes all I can do is shake my head..

I'm not convinced that every $0.1 matters in 'good' products.. Cheap crap, yes, that is why so many have bad caps in their power supplies..

But 'good' products, the price reflects it.

I'm still not sure the point of including the microSD slot when the read/write speed is so slow though..

Using USB for system storage can be very shaky.

Using USB for system storage can be very shaky.

Are you speaking in general terms? Or RouterOS specifically?

In general, USB is "shaky" from the memory used..

I'm running dozen of servers from USB flash drives, be it x64 ROS or TrueNas and never had any problems. USB booting is widely supported, it's easy to image the drive for a quick backup and for ROS it also means license is bound to the drive, not a server so HW upgrades are easy.
As long as you buy good brand flash drives and not "$3 Aliexpress special" they will likely outlast rest of the hardware, unless you do huge amount of writes or something. In that case SSD would be a better choice. But in general any modern flash drive will have better wear leveling and ECC than built in flash/NAND in routerboards Mikrotik uses. So unless USB support in ROS is broken when used for container storage (we will see...), it should have better performance than using internal flash memory.

Using USB for system storage can be very shaky.

Are you speaking in general terms? Or RouterOS specifically?

In general, USB is "shaky" from the memory used..

In general. USB controllers have a habit to reset when the load to "high". Command queueing doesn't seem to work at all, and is very prone to damage modern filesystems during lockups.