By: Adrian (email@example.com), November 4, 2021 6:56 am
Room: Moderated Discussions
The embargo has expired, so the reviews have become public.
It was expected that Alder Lake will be much faster in single thread in all cases.
In most cases it is faster in single thread. Sometimes the advantage is around 20%, as expected, but there are also many cases when the advantage over Zen 3 is much less.
More weird is that in single-thread Cinebench, when run at the same fixed frequency, it has exactly the same speed as Zen 3, even if that is much faster than Rocket Lake. So it looks like in many cases the advantage in single-thread is determined more by the high clock frequencies and the much faster DDR5 memory, than by the improvements in IPC, as expected.
For multi-threaded applications, unfortunately for Intel, even the new improved Intel 7 manufacturing process remains much behind in energy efficiency compared to the TSMC 7 nm process.
Ader Lake with 24 threads can be considered as having equivalent performance with Zen 3 with 24 threads.
In some multi-threaded benchmarks Zen 3 is faster, in some others Alder Lake is faster and in a few benchmarks Alder Lake succeeds to match even the more expensive Ryzen 9 5950X.
Nevertheless this MT performance is obtained only at 50% higher power consumption (240 W over idle for Alder Lake vs. 160 W over idle for Zen 3). Moreover, you need a very good cooler, like for Threadripper, to obtain such results.
So the energy efficiency of Alder Lake, even with 1/3 of the threads on Gracemont cores, is only 2/3 of the energy efficiency for Zen 3 using TSMC 7 nm, which is pathetic.
I assume that this low energy efficiency is caused by Intel being desperate to match the performance of desktop Zen 3 and running Alder Lake at too high clock frequencies.
It is likely that at lower clock frequencies, as in laptops, Alder Lake will be much more efficient energetically, but it remains to be seen whether it will be able to match CPUs using the TSMC process.
This does not look good for Sapphire Rapids, but again, maybe at the lower clock frequencies from servers, the Golden Cove cores will be more efficient than what is seen in desktop Alder Lake.