Yes, it does. SD cards are not really designed for being used as a root file system. They are OK at streaming writes and reads, but once you start getting non sequential they slow down like you wouldn't believe. Which, yes, I know, is super weird for what should just be some glue logic around a NAND.
I was investigating corruption and performance problems with our root filesystem on an SD card. The cards would be great a obvious benchmark style tasks, but when I recorded the block access pattern from our driver and replayed that on a Linux desktop with O_DIRECT, we'd not only get under 200KiB/s average access speed (which matched what we were seeing on the embedded system), but we would also get corrupted sectors (ie. we write it just fine, but we just get an error back from the card when we go to read the sector) in less than a day of sustained writes (once again at only 200KiB/s). And this was with high quality SanDisk cards that were then verified by them to be real cards (for a while we thought that clones had made their way into our supply chain). Using a weird form factor eMMC chip in an SD card got rid of these issues. There's also "industrial" SD cards that are around the same price that I suspect are basically the same thing.
Most SD and μSD cards have embedded microcontrollers http://www.bunniestudios.com/blog/?p=3554 — I wonder how much of the corrupted-sector problems you were getting are really just bugs in their firmware? Or things that could be worked around with better firmware?
Yeah, it was almost certainly firmware bugs combined with already marginal NANDs. ie. the NANDs probably would have been fine if they were babysat a little better, but they were probably bottom of the barrel. That's kind of the SD card market in a nut shell any way.
That being said we tried many different SD cards from quality vendors and found pretty heavy bugs and performance related issues among all of the non "industrial" versions.
So, yes, the problems don't have to be intrinsic to the form factor, but empirically you're more likely than not to have issues with them.
I was investigating corruption and performance problems with our root filesystem on an SD card. The cards would be great a obvious benchmark style tasks, but when I recorded the block access pattern from our driver and replayed that on a Linux desktop with O_DIRECT, we'd not only get under 200KiB/s average access speed (which matched what we were seeing on the embedded system), but we would also get corrupted sectors (ie. we write it just fine, but we just get an error back from the card when we go to read the sector) in less than a day of sustained writes (once again at only 200KiB/s). And this was with high quality SanDisk cards that were then verified by them to be real cards (for a while we thought that clones had made their way into our supply chain). Using a weird form factor eMMC chip in an SD card got rid of these issues. There's also "industrial" SD cards that are around the same price that I suspect are basically the same thing.