I have a VPS server running Windows 2012 R2 that is used with a piece of software that makes roughly 15,000 connections in a minute. I noticed some lag and other issues with the VPS, and decided to upgrade to a Dedicated server.
VPS Specs: "4 vCores 3.1 GHz, 8GB Ram, SSD, 100mbit connection" Dedicated Specs: "Xeon E5-1620 v2 3.7GHz, 64GB RAM, 1gbit connection"
I installed Windows 2012 R2 on it, and noticed a dramatic speed decrease in the software. It was hitting only about 5,000 connections per minute. I thought it might be because this was on a HDD instead of an SSD, so I setup a RAMDisk. There was zero improvement in the performance. I started to look into TCP limitations, thinking the VPS container that was automatically setup for me might be different than my settings. I couldn't find much. I added a ton of options to the TCP Parameters in the registry, and still see no difference.
The software connects to a single IP address, across multiple ports (~100 ports).
I'm unsure of where to look now. All speed-tests show the dedicated server is significantly faster than the VPS, but the VPS, with a slower connection and less powerful hardware, can reach faster connections per minute.
Any direction to where I can look further would be appreciated.