Quote from segv:
There is a lot of misinformation in this series of posts. I would say that the common reason that a trader has more than one processor is that they are misinformed. The majority of performance problems can be attributed to poorly written software. If the software is poorly written, a second processor will probably do little to speed improve performance. Multiple processors make sense when you may have two independent CPU-intensive threads operating on independent data simultaneously. Whenever these threads share a common resource there is a deadlock where one operation must wait on the other to complete. This implies that there must be a way for separate programs to operate on a common resource without stepping on one another. In software engineering terminology this is referred to as "locking". Locking is itself a CPU intensive operation, meaning that there is an overhead associated with multiprocessing. The locking overhead is associated with the frequency of common data access by the respective threads. Depending on the software and operating system, there might be no performance improvement as a result of having parallel processors. Even worse, performance could actually decrease as a result of locking. This does not even scratch the surface, but it should be sufficient to say that the majority of trader workstations will not benefit from multiple processors. To benefit, the software needs to be carefully designed to take advantage of the additional processors. Even then, there are operating constraints that must be accounted for to ensure performance. The bottom line is, "save your money". If you have totally separate applications, consider purchasing a second system instead of a second CPU.
-segv