Weird question ?

[dragoncurt]

Hi can someone tell me the difference between an older version of a CPU which can do for example quad core at 3GHz vs a new quad core at 3GHz. Isn't it in theory the same speed ? 

 

I know I should know better but just wondering why.v

 

Thanks 

[79wjd]

The IPC (instructions per clock -- efficiency of each ghz) generally increases between generations (CPU architectures/design nodes), as does the power consumption. 

 

So, a Skylake i5 at 3.1ghz would be about 10% faster than a Haswell i5 at the same 3.1ghz due to the each mhz of the Skylake CPU producing more power. 

 

*Architecture: the layout of the transistors/circuits. 

*Design nodes: The size of the gap between traces on the cpu itself (think of a cpu as consisting of billions of tiny wires, the node is the amount of space between those wires).

[Streetguru]

2 minutes ago, dragoncurt said:

Hi can someone tell me the difference between an older version of a CPU which can do for example quad core at 3GHz vs a

newer processors can do more instructions per cycle/clock, so no they aren't the same, the most famous example, aside form modern AMD vs Intel, is the pentium 4 vs Core 2 Duo

 

 

 

[The Cool n00B]

There's lots more to it than specs on paper. New CPUs have newer architectures and features, for example Skylake has 20 PCIe lines unlike Haswell which has 8(?). One of the most noticeable differences from Skylake to Haswell (at least in synthetic benchmarks) is a better IPC, or Instructions Per Clock, meaning it can do more every time the clock runs, further meaning that .1 GHz has a larger improvement, if that makes any sense.

 

Not all GHz are created equal.

[Ben_Upde]

It's all about the IPC (instructions per clock cycle). Typically newer generations have a better IPC rating than previous generations, making them faster at the same speed rating. This is also why AMD processors suck so badly currently. They have high speed ratings but lower IPC so they are inherently slower. 

[unidentical]

As djdwosk97 says and usually it's about a 10% performance improvement per generation at least on the Intel side. 

[dragoncurt]

Oh okay. Thank you very much guys.