AMD Ryzen 5000 Series / Zen 3 Launch

[smitty3268]

We don't want products which are slower that we already own nor buying the same performance for the same price.

Agreed. But even in the worst case here, you are getting 20%+ performance from the 5600X vs the 3600XT, for a 20% price increase. So it's pretty much flat. And the more expensive chips are better, because you're getting that 20%+ performance boost with a 10% (or whatever) price increase.

I think that's why it seems a little strange to see people going crazy over these price increases. They're still better value than the last gen.

[AdrianBc]

10nm i7-1185G7 has a maximum clock of 4.8 GHz when running a single thread. It is therefore unlikely for 14nm Rocket Lake to be able to reach 4.8 GHz in single-threaded mode. Notebook CPUs (28W TDP) have approximately the same single-core boost frequency as desktop CPUs (about 100W TDP, but only when multiple cores are utilized). 14nm Rocket Lake (Willow Cove arch) will most likely have lower boost frequency than 14nm Comet Lake (Skylake arch) because the former is a more complex design than the latter.

The reason why Intel backported a 10-nm design to 14-nm, creating Rocket Lake, was precisely to reach higher clock frequency, because the limit for their current SuperFin process is 4.8 GHz.

It is certain that Rocket Lake will reach at least 5.0 GHz (seen in engineering samples). It is not known if it will reach as high frequencies as the Skylake derivatives, i.e. at least 5.3 GHz, but we do not know yet any reason that could prevent this.


Nevertheless even if Rocket Lake would succeed to take back the title of being the fastest CPU in single thread applications, that would be just by a few percent, while the multi-threaded performance will be very low compared to Zen 3 or even Zen 2, so it could be recommended only for hardcore gamers, who use their computer for nothing else but games.

[AdrianBc]

The reason why Intel backported a 10-nm design to 14-nm, creating Rocket Lake, was precisely to reach higher clock frequency, because the limit for their current SuperFin process is 4.8 GHz.

It is certain that Rocket Lake will reach at least 5.0 GHz (seen in engineering samples). It is not known if it will reach as high frequencies as the Skylake derivatives, i.e. at least 5.3 GHz, but we do not know yet any reason that could prevent this.


Nevertheless even if Rocket Lake would succeed to take back the title of being the fastest CPU in single thread applications, that would be just by a few percent, while the multi-threaded performance will be very low compared to Zen 3 or even Zen 2, so it could be recommended only for hardcore gamers, who use their computer for nothing else but games.

Above, I was not clear enough regarding what atomsymbol said "14nm Rocket Lake (Willow Cove arch) will most likely have lower boost frequency than 14nm Comet Lake (Skylake arch) because the former is a more complex design than the latter".


Being a more complex design means doing more per clock cycle, thus consuming more power at the same frequency. This leads to a lower clock frequency in multi-threaded applications, when the power consumed by the CPU is limited by cooling.

In single-threaded applications however, the active core consumes much less than the TDP, e.g. about 50 W, and the clock frequency is limited by the single-core maximum turbo frequency.

So it does not matter that a Rocket Lake core is more complex. That will limit the base frequency to a lower value compared to a Comet Lake with the same number of cores, but that does not limit the maximum turbo frequency, so there is no reason why Rocket Lake could not reach 5.3 GHZ or even more.

Of course, there might be some details of the microarchitecture that could still limit the maximum frequency to a lower value than for Comet Lake, but we do not know yet anything about that.

Moreover, such a lower limit for the clock frequency due to logical design is very unlikely, because the only motivation for the Rocket Lake project was to reach higher frequencies, to have a chance to compete with Zen 3. Intel would never have spent so much money for this project without hoping to reach very high frequencies. It remains to be seen whether they will succeed.

[atomsymbol]

The reason why Intel backported a 10-nm design to 14-nm, creating Rocket Lake, was precisely to reach higher clock frequency, because the limit for their current SuperFin process is 4.8 GHz.

It is certain that Rocket Lake will reach at least 5.0 GHz (seen in engineering samples). It is not known if it will reach as high frequencies as the Skylake derivatives, i.e. at least 5.3 GHz, but we do not know yet any reason that could prevent this.

Nevertheless even if Rocket Lake would succeed to take back the title of being the fastest CPU in single thread applications, that would be just by a few percent, while the multi-threaded performance will be very low compared to Zen 3 or even Zen 2, so it could be recommended only for hardcore gamers, who use their computer for nothing else but games.

Above, I was not clear enough regarding what atomsymbol said "14nm Rocket Lake (Willow Cove arch) will most likely have lower boost frequency than 14nm Comet Lake (Skylake arch) because the former is a more complex design than the latter".

Being a more complex design means doing more per clock cycle, thus consuming more power at the same frequency. This leads to a lower clock frequency in multi-threaded applications, when the power consumed by the CPU is limited by cooling.

In single-threaded applications however, the active core consumes much less than the TDP, e.g. about 50 W, and the clock frequency is limited by the single-core maximum turbo frequency.

So it does not matter that a Rocket Lake core is more complex. That will limit the base frequency to a lower value compared to a Comet Lake with the same number of cores, but that does not limit the maximum turbo frequency, so there is no reason why Rocket Lake could not reach 5.3 GHZ or even more.

Of course, there might be some details of the microarchitecture that could still limit the maximum frequency to a lower value than for Comet Lake, but we do not know yet anything about that.

Moreover, such a lower limit for the clock frequency due to logical design is very unlikely, because the only motivation for the Rocket Lake project was to reach higher frequencies, to have a chance to compete with Zen 3. Intel would never have spent so much money for this project without hoping to reach very high frequencies. It remains to be seen whether they will succeed.

Maximum CPU frequency (boost frequency) depends on two factors:

• The length of the critical path of a pipeline stage. In a simplified view: max frequency = the speed of light divided by the length of the critical path; the speed of light is a constant.
• An increase in frequency requires an increase in current and/or voltage for the CPU to operate correctly at the higher frequency. This generates additional heat that does not contribute to computation and has to be moved away from the CPU die before it will result in a hardware error.

It is likely that the x86 CPU with the shortest critical path ever designed was Pentium 4 (NetBurst architecture, Prescott core) with 31 pipeline stages. This was able to reach 3.2 [email protected] and 3.73 [email protected] using conventional (metal+air+fan, no water/nitrogen) cooling.

• More pipeline stages enable a shorter critical path (because the CPU's work is being subdivided into smaller units)
  • Excessive focus on shortening the critical path results in a lower IPC (instructions per clock) of the CPU (Pentium 4)

It is likely that Pentium 4 Prescott would be able to easily reach over 6 GHz on conventional cooling if manufactured using 14nm technology.

Skylake and Sunny Cove have the same number of pipeline stages: 14-19.

The length of the critical path depends on the number of transistors used to perform a particular function. Sunny Cove increases the size of the L1D cache to 48 KiB (Skylake: 32 KiB). Sunny Cove L1D latency increases to 5 cycles (Skylake: 4-6 cycles).

It is possible, although unlikely, that Sunny Cove with a much larger CPU core than Skylake has a critical path of the same length as Skylake (because of more advanced (better tuned) algorithms in Sunny Cove).

https://en.wikichip.org/wiki/intel/m...kylake_(client)
https://en.wikichip.org/wiki/intel/m...res/sunny_cove
https://software.intel.com/content/w...ce-manual.html