I'm not affiliate with Amazon.com in anyway. Been hunting for an affordable fast UHS-II SDXC or SDHC card to record 4K video in my Lumix LX100 camera hence found these deals but not sure when they'd expire. If you are after fast SD card for 4K video recording then these Lexar UHS-II cards will serve you well. Don't bother with 633x cards as I have had issue recording 4K in 30P mode.
List Price: $194.99USD Sale Price: $94.86USD + $5.26USD Shipping to Australia - You Save: $100.13USD (51%)
* High-speed performance-leverages UHS-II technology (U3) for a read transfer speed up to 2000x (300MB/s)
* Includes SD UHS-II reader for high-speed file transfer from card to computer, dramatically accelerating workflow
* Captures high-quality images and stunning 1080p full-HD, 3D, and 4K video with a DSLR camera, HD camcorder, or 3D camera
* Includes downloadable Image Rescue software to recover most photo and select video files
* Backwards compatible with UHS-I devices
Customer Review & Speed Test Results: http://www.amazon.com/review/R2MGT0RYKE57I8
Also check out Lexar Professional 1000x SDXC UHS-II/U3 Card (Up to 150MB/s read) w/Image Rescue 5 Software LSD256CRBNA1000
256GB: List Price: $575.99USD Sale Price: $148.83USD + $5.14USD Shipping to Australia - You Save: $427.16USD (74%)
128GB: List Price: $184.99USD Sale Price: $74.95USD + $5.05USD Shipping to Australia - You Save: $110.04USD (59%)
64GB: List Price: $103.99USD Sale Price: $39.90USD + $5.29USD Shipping to Australia - You Save: $64.09USD (62%)
- High-speed performance-leverages UHS-II technology (U3) for a read transfer speed up to 1000x (150MB/s)
- Captures high-quality images and extended lengths of stunning 1080p full-HD, 3D, and 4K video with a DSLR camera, HD camcorder, or 3D camera
- Large capacity options up to 256GB let you enjoy shooting longer without changing cards
- High-speed file transfer from card to computer to dramatically accelerate workflow and includes downloadable Image Rescue software to recover most photo and select video files
- Backwards compatible with UHS-I devices and backed by expert support and limited lifetime warranty
Customer Review & Speed Test Results: http://www.amazon.com/review/RU5TH0J1NQUX6
AFAIK the LX100 will not be able to take full advantage of the UHS-II interface.
You don't need these for 4k video. A Sandisk extreme or extreme pro (the new U3 ones) or equivalent, such as samsung evo pro, is plenty. Those can be had for a fraction of the price from Australian Retailers - have a look at staticice and ebay.