Regarding SD card speeds, I found that slower cards (lower Class) are often faster when used with Arduino. Reason is that the Class specifies the performance in the highest speed mode while the Arduino board accesses the card through a much slower legacy mode. So what matters is the speed of the legacy mode and that is not reflected by looking at the Class rating.
So if you have a different card with a different brand and/or different Class, it may work better.
I don't know the buffer size used for writing in Tapuino, but the larger the better speed you can achieve and if running off a Nano, there is not room for much buffers. Single byte writes are really slow due to massive overhead. I did a few SD write benchmarks on an Arduino a little while back and found that I needed 8k or so write buffers to be able to keep up with the fastest tape pulses I could find, so effectively using all of the memory in a Nano.
So if you have a different card with a different brand and/or different Class, it may work better.
I don't know the buffer size used for writing in Tapuino, but the larger the better speed you can achieve and if running off a Nano, there is not room for much buffers. Single byte writes are really slow due to massive overhead. I did a few SD write benchmarks on an Arduino a little while back and found that I needed 8k or so write buffers to be able to keep up with the fastest tape pulses I could find, so effectively using all of the memory in a Nano.
