The problem is that it does not seem to work. I began recording a video, but it only lasted 20 seconds or so. So, I decided to investigate, as usual. I ran a simple little command-line program to test a bunch of card speeds.
DEV=/dev/sdc1; umount $DEV; mount $DEV sdcard/; sync; date; time dd if=/dev/zero of=sdcard/zeros.txt bs=1024 count=$((1<<17)) conv=fdatasync; date; sync; date; rm sdcard/zeros.txt; umount sdcard/
I tried this procedure with 9 different SD cards and an el-cheapo multi card reader. which you can see below:
|Eye-Fi||64MB SD from Garmin GPS||4GB SDHC Patriot|
|2GB Crucial||2GB Sandisk Ultra II||Newer 2GB Sandisk Ultra II|
|4GB Kingston||4GB SDHC "Polariod" PNY||4GB SDHC Transcend|
The Eye-Fi is even slower than a 64MB MicroSD card that I got with my Garmin GPS, but have never used since it is so tiny. Of those 4GB SDHC cards, I'm pretty sure none of them were over $20; they're all super generic. The Sandisk cards were about $100 when I bought the first one over three years ago.