Discussion Intel Nova Lake in H2-2026: Discussion Threads

[LightningZ71]

And remember, the E cores only need to be orthogonally complete, they do NOT have to be performant on AVX512 code. Double pumped 256 data paths like AMD's mobile cores? Yes please. Quad pumped 128bit paths? Why not. Extra XTORS for higher clocks? Don't think so.

 

[Jan Olšan]

APX doesn't quite sound as something with high risk of being an errata minefield. TSX you can absolutely see how, but APX?

 

[adroc_thurston]

APX doesn't quite sound as something with high risk of being an errata minefield

This is Intel we're talking about, they shipped broken ECC on *Xeons*.

 

[DavidC1]

And remember, the E cores only need to be orthogonally complete, they do NOT have to be performant on AVX512 code. Double pumped 256 data paths like AMD's mobile cores? Yes please. Quad pumped 128bit paths? Why not. Extra XTORS for higher clocks? Don't think so.

There's only 12% difference by enabling 512-bit datapath. Most of the AVX512 gains are because of the instruction set.

AVX-512 Performance With 256-bit vs. 512-bit Data Path For AMD EPYC 9005 CPUs Review - Phoronix

www.phoronix.com

Off: 1x
256 mode: 1.3x
512 mode: 1.45x(12% over 256 mode)

There's better ways of using transistors rather than wasting power and die for 512 bit vector units, which is a big increase. Like if they improved the uarch further, it would bring gains everywhere, including on AVX512 workloads. A hypothetical future core that's 256 mode but gains extra 5% due to further uarch improvements would reduce the differences versus 512 mode to a mere 6%, while being faster everywhere else, lower power, and smaller core size.

For AMD, 256 mode Zen 6 will likely be equal to 512 mode Zen 5. Yes in cornercase scenarios it'll be better, but you are bandwidth limited in most cases, and end up better in power and area.