Processors: Frequencies. hyperthreading?

Question

Processors

At the moment I'm working on game servers on the Source engine. Now on one of the computers with an Intel i7-920 processor operating in Hyper-Threading mode , 6 Counter-Strike: Source servers have been raised with each server bound to a separate core (thread). Since there are 4 cores (8 threads), and the server engine can only work in single-threaded mode, you can ideally raise 8 CS servers.
With the increase in the popularity of servers, the load on the stone has also increased. 6 threads out of 8 are now working at 90-99% and this affects the FPS and sometimes leads to lags.
Question 1
Intel Core i7 920 @ 2.67GHz - what is this frequency? Kernels? All cores? One thread? How to find out the frequency of each thread (Debian OS)?
Question 2
It is possible to buy an Intel Core i7 980X (which is 6-core and in XT mode gives 12 pots). Please tell me, are the flows “stronger” in this stone than in the previous processor? Or is the advantage here only in their number, and the flow itself is weaker? Similar to the previous Intel Core i7 980X @ ​​3.33GHz - what is this frequency? What is the frequency of cores and threads if such a question is relevant here?
Note
Disabling HyperThreading on the server is prohibited by DC

Answer 1

1) The frequency of one core. Streams have no frequency. Threads are executed on real (physical) cores. Because of HT, the system sees 8 cores at 2.67 GHz each, but this is virtual parallelism.
2) It is better to buy another 1,920 (although 2600K is better). 980 is not a very smart investment.

Answer 2

If you are talking about a hatzner, then take KVM and turn off HT. Only when you refuse the server will you switch back.

Answer 3

It is better to look at completely different characteristics. It’s better not to focus on the frequency and the number of cores, but on the memory bandwidth, cache size, and all that. Your servers do not depend on each other, therefore, for example, two dual-core processors with QPI would be more efficient than one four-core one.
A large number of threads can make performance even worse, due to the increased load on the memory access hardware.
Therefore, it is really better to buy another processor, there will be an additional cache and an additional memory access strip.

Answer 4

It would be nice to check the length of the disk queue. Maybe the plug is not in the processor.
If the data does not have time to be read from the disk, then the processor will wait a long time for it to be read.
Well, check if there are any unnecessary calls to the swap.
About hyperthreading. This is virtual parallelism. It is calculated that different threads will more fully fill the pipeline with commands, and, accordingly, the overall system performance will increase. But the performance of each individual process can drop.