David "Dave"
This is called &#34;Class 10&#34;, so I ordered it, figuring it would have useable speed. I plugged it in to copy about 9GB of program installation files. I was totally dumbfounded that it took about 3 hours to copy those files onto this &#34;Ultra&#34; &#34;Class 10&#34; SDXC card. (9GB on my super-slow, super-cheap plastic school-kid USB thumb drive takes less than 10 minutes.) So then I tested it on various known computers with typical raw and JPG picture files. Read speeds ranged from 15-25MB/s, while write speeds ranged from 4-8MB/sec for big files, and below 1MB/sec for small files. This is what I would call largely unusable. VERY disappointing.