Intel is planning to offer an 8-core version of its hybrid Alder
Lake chip—without efficiency cores—and will apparently offer AVX512
support too, according to a developer guide released by the
The two tidbits were in a gaming software developer guide Intel
released on its website to help game developers prepare for its
12th gen Alder Lake CPUs. Among the surprising reveals in the
developer guide are plans for an Alder Lake model that won't even
be hybrid at all.
Mobile SKUs will feature up to 6 P-cores and 8 E-cores. All
mobile SKUs will include E-cores. Desktop SKUs will feature up to 8
P-cores and up to 8 E-cores. Specific desktop SKUs will feature
only P-cores, the guide says.
The news of a performance core version, or P-core only model
without the efficiency cores, is a bit of a surprise as Intel has
had no hints of offering versions without the E-cores. It also
makes you wonder just where an Alder Lake chip without E-cores—e
ssentially removing the hybrid component—slots in. Are they
lower-cost, clock-limited versions, or are they specially tuned
chips aimed for very high-clock speed applications where having
more cores doesn't matter? That's something we'll have to wait for
more information on, but that wasn't the only surprise.
The developer guide also revealed that Intel will indeed offer
support for AVX512 after all on Alder Lake. Intel officials had
previously said would be permanently disabled on the Alder Lake
The guide, however, contradicts that, saying the
much-maligned AVX512 would continue on.
AVX512 is disabled on P-cores when E-cores are enabled because
AVX512 is not supported on the current E-core architecture. It is
ultimately up to the Original Equipment Manufacturer (OEM) whether
the option to disable the E-cores is exposed in the Basic
Input/Output System (BIOS), the software guide says. And yes, Intel
referred to it as BIOS, so shake your fist at the clouds, UEFI
Intel just revealed a
non-hybrid version of the 12th gen Alder Lake is on tap.
Written by Philipp Gerasimov, Marissa Du Bois and Leigh Davies
(all three of whom work as graphics and game engineers at Intel),
much of the guide is aimed at game developers and gives examples of
where developers should want to take advantage of the E-cores and
the P-cores. Part of that advice is for developers to write games
that don't try to hammer all available cores in a CPU just because
those cores are there.
Testing has revealed that some legacy software can show a
performance inversion as you increase core counts, the software
guide says. This is not an issue specific to Alder Lake, but more
of a scalability challenge. As the number of threads increases, so
does the overhead of managing them.
If there isn't enough work for the threading system, the
overheads can become greater than any benefit derived from
increased work distribution. Developers shouldn't naively scale to
the available core count on the system, but instead scale to the
point where benefits decrease below a threshold decided by the
programmer. This allows the OS more opportunities to manage
hardware resources, parking unused cores and diverting power to the
parts of the system that need it, potentially increasing
Some will say this is Intel telegraphing a weakness of its new
hybrid design, but the paper does shed a little more light on how
Alder Lake will perform in gaming.
Analysis of games on hybrid architectures has shown the majority
of games perform well, with older, or less demanding, games
favoring the Performance cores. Games that were already built to
heavily utilize multithreading, and that can scale to double-digit
core counts, were found to benefit from hybrid architecture due to
better throughput. However, there are inevitable performance
inversions, attributed to either poor multithreading game
architectures, poor OS scheduling, or increased threading
The guide recommends that developers basically keep their
libraries and development tools updated to get the best out of
Intel said for titles where there is no optimization, its Intel
Thread Director will try to dispatch work to the proper P-core or
E-core. But the guide also admits there can be times when tasks
aren't assigned to the right core.
What does this all mean? We're probably in for some surprises
when Alder Lake is released with some games screaming and some
leaving us with head-scratching results.