Leaked Patch Confirms AMD Zen Will Have 32 Cores per Socket

By  /  5 months ago
AMD Zen Chipset

A leaked Linux patch on LKML.org, first spotted by The New Citavia Blog, suggests that AMD Zen based processors will feature up to 32 physical cores. The patch also hints at the similarity of parts of the “Zen” and “Zeppelin” codenames.

The Zeppelin codename was first mentioned back in August last year, and parts of the patch identify it as a “family 17h model 00h” CPU:

AMD Zeppelin (Family 17h, Model 00h) introduces an instructionsretired performance counter which indicated byCPUID.8000_0008H:EBX[1]. And dedicated Instructions Retired register(MSR 0xC000_000E9) increments on once for every instruction retired.

There’s also an older patch from November last year, on the same mailing list, which reveals a little more info about the upcoming Zen architecture. However, the most important part is the code which describes how the last level cache (LLC) ID is being calculated for Zen based MPUs:

+ core_complex_id = (apicid & ((1 << c->x86_coreid_bits) - 1)) >> 3;
+ per_cpu(cpu_llc_id, cpu) = (socket_id << 3) | core_complex_id;

The above code mentions "core complex," which accoding to Dresdenboy refers to "compute unit" and has already been used in some AMD patents. Dresdenboy explains the above code as follows:

The expression marked in red means a shift right by 3, which equals a division by 8. So with two logical cores per physical core due to SMT, a core complex should contain four Zen cores and a shared LLC.

The next line shows the socket ID being shifted left by 3, leaving 3 bits for the core complex ID, which suggests a maximum number of eight core complexes per socket, or 32 physical cores. This number should first be seen as a placeholder, but we've already seen rumours mentioning that many cores.

Built on a 14 nanometer architecture, Zen architecture features a unified AM4 socket with its GPU-equipped APU counterparts, as well as includes support for DDR4 memory. If a previous report is to be believed, it will bring greater than 40% IPC increase over their current generation.

The first Zen based chips are scheduled to arrive at the end of this year, with APUs arriving sometime in 2017.


Join the Conversation

Hot Right Now

AMD Zen Chipset

AMD Only Producing Octa-Core Zen Summit Ridge CPUs in the Initial Wave

A new report has just surfaced on the web which suggests that AMD will only be producing octa-core...

by   /   2 months ago
SparseLightVR_Microsoft_VR-nausea

Microsoft Proposes a Cheap Solution to Eliminate Nausea on AR and VR H…

Virtual reality, as a market, is currently in its budding form, but the domain is progressing...

by   /   2 months ago
Sapphire R9 390 Toxic_1

Radeon R9 390 Toxic Features The Highest Factory-overclock by Sapphire

While AMD Polaris--the next-gen GPU architecture--is just around the corner, OEMs can't stop...

by   /   2 months ago
Intel Broadwell-E Core i7-6850K CPU_1

Intel Core i7-6850K Pictured and Benchmarked, ~10% Higher IPC Than Has…

Photos of the Intel's upcoming six-core Core i7-6850K have just made their way to the web thanks to...

by   /   2 months ago
asrock-updates-bios-x99-motherboards-support-broadwell-e-cpus

ASRock’s New BIOS Updates for X99 Boards Add Support for Broadwell-E…

With the launch of Intel Broadwell-E CPU lineup just around the corner, ASRock has issued out new...

by   /   3 months ago
Load More