cpu speeds and cores

[chucky9]

So if a quad can perform 4 processes per second and a 8 core can do 8 what does oc actually do and why does a 4ghz quad core perform so much better than a 1ghz quad and does this effect change depending on the cpu? is laptop vs desktop vs server cpu's?

 

[InvalidError]

The overall performance of a CPU = number of cores * clock * average instructions per clock for a given workload and CPU architecture * multi-threaded scaling of that software

Most mainstream software is poorly threaded so the multi-thread/core scaling is well below 100%. More simultaneously active cores also increases the likelihood of having some increased latency which will reduce the IPC so the hardware itself does not scale quite perfectly even with near-ideal software either.

OCing affects the clock part of this equation. Overall performance is a result of all the factors above and many other more subtle ones.

 

[chucky9]

is that why i feel like my 8 core is gives the same performance as a quad core?

 

[Guest]

chucky9, I'd just like to add what I've "discovered" lately when comparing Intel CPUs. More cores also require more power. I don't know why yet. Somehow running more cores require more power, so the overall clock speed is reduced to minimize heating. And conversely fewer cores also let the CPU run at higher clock speeds. I've found some statistics showing that dual-core CPUs can actually outperform quad-core CPUs to some degree. Probably it's best to strike a balance between clock speed and cores if your're shopping for a CPU.

 

[chucky9]

see although i am currently still heavily learning about cpu's and gpu's as it is what i want to specilise in at uni i still find stuff like that interesting. but im just wondering because watch dogs and the division recommend a mid to high end i7 gtx 690 10gb ram or a 8core hd 7990 10gb ram and i currently have a amd 8 core gtx 780 (missed out on the gtx 780 ti and the three games deal pissed me the hell off) and 16gb ram and soon to have a h100i so ive been thinking if i have all of that surely i can out perform a quad core but it feels like i cant so is that a bad config of hardware or just bad coding?