So looks like Asus just released a standalone since port 10gb nic for 100-120$. Looks like it is just a repackage of what they were already bundling with some of their motherboards. I have the older version and have not had any issues with it.
Specs have it drawing only 6.5w and it also support 2.5gb and 5gb speeds.
ASUS XG-C100C 10G Network Adapter PCI-E x4 Card with Single RJ-45 Port and built-in QoS for Use with Windows 10 / 8.1 / 8 / 7 and Linux Kernel 4.4 / 4.2 / 3.6 / 3.2 (XG-C100C) - Newegg.com
Specs have it drawing only 6.5w and it also support 2.5gb and 5gb speeds.
ASUS XG-C100C 10G Network Adapter PCI-E x4 Card with Single RJ-45 Port and built-in QoS for Use with Windows 10 / 8.1 / 8 / 7 and Linux Kernel 4.4 / 4.2 / 3.6 / 3.2 (XG-C100C) - Newegg.com