Recommendation for 10gb PCI-E NIC?

Switch: 10Gb RJ45 Router: 10GB RJ45 NAS: 10Gb RJ45

Seems a shame to not have 10G-baseT on my desktop.

I have an older home built machine, built on a MSI Tomahawk B450. I'm not looking to upgrade at the moment, but I have an empty PCIe 2.1 x16 slot.

I don't expect to be able to guarantee 10Gb ethernet speeds with my motherboard and CPU, but I'd like to get close. I've seen that Intel X540 NICs don't have any power saving/thermal modes, so they should be avoided. Aquantia apparently was acquired be Marvell and basically ignored to death -- and the AQC113 has rumors of an unfixable bug that sometimes leads to it not being recognized at system boot. Realtek doesn't have a chips/boards available yet, and Broadcom costs two arms, two legs, and three noses.

Any suggestion on what to get? Bonus for PCIe 2.1x16 over PCIe 3x8, really want to stay under $100US.