We have now added a beta option called the "Extreme accelerator" to our order page
that further allows Source and Orangebox-based servers to run at up to 10,000 FPS. This setting is made possible by exclusive code changes that we have made to the Linux kernel.
For the same reasons that 2000 FPS servers are theoretically better than 500 FPS servers (more accurate timestamps, less work to do in each frame, and smaller sleep quantums), 10k FPS servers are theoretically better than 2000 FPS ones. We initially did not think that the human mind could see a difference, but in our testing, some players did say they saw an improvement.
This feature is said to be in beta because we are still evaluating whether it meets expectations and is worth the extra cost to both us and our customers. If you rent an extreme accelerated server, we would greatly appreciate any feedback you can provide us on it.