Slow Writes to SD Card

Sequence Generator
1

I just installed a 400GB Sandisk SD card into my Surface Pro 3 for storing SGP photos. However, it takes 14 seconds for an image to finish saving, where it takes about 2.5 seconds if I do it on the “C:” of the surface. Attached is the log output surrounding my taking of flats this morning, I swapped from “D:” to “C:” , D is the SD-Card, C is the internal SSD of the Surface Pro.

I used a memory speed test program to write a 512MB file to the SD card to see if the card was the issue and I get 50MB/S so I’m puzzled why it takes so long to download the 32MB files.

My Camera is the ASI-1600MM-Cool, but since it writes speedily to the internal drive, I don’t think this is a contributing factor.
SGP_Slow_SDCard.txt (13.2 KB)

2

I don’t have a surface, so not sure of its connectivity, but how have you connected the SD Card, direct to the internal disk bus or via an external USB 2\3 port (much slower)? Also how is the disk formatted FAT32\NTFS ? If the formatted block size is non standard, this can sometimes have performance issues also is there writeback checking and antivirus checking on the SD disk, best to tell the AV to ignore the target folders.

I personally save the image files, from my 1600mm cool, to a disk store on the local network (gigabit) and that usually takes 5\6 seconds.