Does CPU speed matter?

[Kragos]

I was wondering does cpu speed affect programs in a way that faster speeds means better performance?

Also if I had a pentium that was 3GHz and a core i-5 that was 2.5GHz, would the pentium be better or the core i-5?

Any why for either answer?

[Septimus]

Depends on what kind of workload/tasks the CPU is performing. If you're doing some heavy single-threaded application work, then a Pentium that is 3GHz would be "faster" than the i5. If you're doing something that utilizes multiple cores, then the i5 would be faster. 

[Kragos]

Just now, Septimus said:

Depends on what kind of workload/tasks the CPU is performing. If you're doing some heavy single-threaded application work, then a Pentium that is 3GHz would be "faster" than the i5. If you're doing something that utilizes multiple cores, then the i5 would be faster. 

What sort of tasks only need 1 thread and which would need more? I mainly use my computer for making documents using microsoft office and the occasional gaming.

[Moress]

Just now, Kragos said:

What sort of tasks only need 1 thread and which would need more? I mainly use my computer for making documents using microsoft office and the occasional gaming.

Any office work or basic use, like web browsing, would only need the pentium. But a majority of games these days will use 2-4 cores. 

[Septimus]

Most of the typical desktop programs that you use will utilize only one or two cores. Games on the other hand typically prefer to have a CPU with four or more cores to run on. 

[Kragos]

Just now, Moress said:

Any office work or basic use, like web browsing, would only need the pentium. But a majority of games these days will use 2-4 cores. 

Okay then so having more cores will help with my games but won't necessarily effect my work?

[Glenwing]

13 minutes ago, Kragos said:

I was wondering does cpu speed affect programs in a way that faster speeds means better performance?

Also if I had a pentium that was 3GHz and a core i-5 that was 2.5GHz, would the pentium be better or the core i-5?

Any why for either answer?

GHz is a measure of CPU frequency, not speed. A 3.0 GHz CPU is not necessarily faster than a 2.5 GHz CPU, it just means it cycles more frequently. How much stuff it actually dies during each cycle depends on the design of the CPU, so a CPU can cycle less frequently but do way more computation each cycle, and overall be faster even with a lower frequency.

 

But yes a CPU at 3.0 GHz will perform better per core than the same CPU (or another CPU of the same design) at 2.5 GHz.