Hope it works well.
8950’s should work for sure. They use about twice the power though as a 8960/8970. You need a power cable from the power supply to power the 8950 as it doesn’t get all it’s power from the pci slot like the 8960/8970, from what I understand.
Instead of add on cards they have started building them into the processor chips. Gen 3 QAT will work with ChaChaPoly for wireguard which they say will be 3x-10.5x more performance.
qat wireguard xeon d2700
Before adjusting all your OpenVPN and HAProxy configurations, I would suggest just trying to download a large file over VPN and see the difference with QAT and AES-NI. It should be very noticeable. Make sure the card is working properly before doing all that work for nothing.
I’m looking forward to see the Xeon D-2700 processors working soon!