I suppose I didn't express my thoughts about dual processors very clearly. Yes, if the work can be divided so that each processor can work independently, two will double productivity. But much of PC computing doesn't lend itself to workload splitting. The majority of computer work is serial in nature: Working on the results of previous work; and completing current work in anticipation for the next process. Since today's CPU speeds result in considerable idleness, overall performance deteriorates little when secondary threads execute during idle moments of CPU capacity that otherwise would be unused as the primary process waits on slower devices. Interestingly enough, the internal micro-code in processors seems ahead of the capabilities of OS or applications in exploiting simultaneous instruction execution.
Where one may perceive a meaningful improvement is speed is dealing with those cases where the primary processor is totally consumed with the task at hand and another thread is forced to wait for execution. In this case, a second processor can alleviate the contention and provide the resources needed to change a waiting system into a performing one. Another advantage of multiple processors is the reduction of time wasted for context switching. However, at today's CPU speeds, I'd be really surprised if humans could discern the difference unless this was a major bottle-neck.
So, it really depends on the application. Some highly specific systems may show improvement, and in rare cases, approach a doubling of performance. But the improvement brought to most general-purpose PC computing through multiple processors will be limited.
I don't know if it's a common practice, but software developers, who should know if the applications they produce can deliver improved performance from multiple processors, should recommend this configuration when advisable. That would be a real assistance to consumers.
Cheers, PW. |
