AlderLake anyone?

[Dobri]

Some basic info about Alder Lake appeared in Forbes, see https://www.forbes.com/sites/antonyl...ap-in-a-decade,

[firejuggler]

Alder Lake price and a first look at
https://www.anandtech.com/show/16959...e-november-4th

[M344587487]

I know the initial parts are the top and mid-range, all of them having a triple digit upper power limit (125W) at base frequency is still concerning. Infinite boost means the upper target is the one to pay attention to out of the box anyway. At the least that sets some high minimum expectations from the Z690 motherboards but probably also does a number on the price.


Anyone looking to maximise bandwidth without OC should make sure to get a board with only two DDR5 slots, intel guarantees up to 4800 DR support on those but only 4400 DR on four slot boards.

[Xyzzy]

https://www.techpowerup.com/review/i...lake-12th-gen/
https://www.techpowerup.com/review/i...lake-12th-gen/
https://www.techpowerup.com/review/i...lake-12th-gen/

[M344587487]

Originally Posted by mackerel

A possible explanation I've seen is that both cores need to share a common feature set. As threads get moved around you can't end up with a situation where code needs AVX-512, but it can't be provided by the E cores. The solution for now is to disable AVX-512 where you have E cores present. Unfortunately they have also said you can't get AVX-512 back by disable E cores and run only P cores. I had hoped something smarter could be done at OS level, where for example code needing AVX-512 would only be run on P cores and not touch the E cores at all.

For consumer level CPUs, for bigger FFTs were way into the region where ram bandwidth is limiting. In that scenario, the loss of AVX-512 is less of an impact, and having faster DDR5 speeds would probably result in a net increase to performance.

Where the loss of AVX-512 will be felt more is for those like me who focus on smaller FFTs that are not limited by ram speeds. The open question remains, just what sort of FMA performance can the E cores provide? It might be a case of quantity over quality to provide a possible net positive in performance.

Apparently you can use AVX-512 by disabling the E cores, but it may depend on the motherboard. This video shows the setting present in a bios: https://youtu.be/fhI9tLOg-6I?t=1650


These things use tremendous amounts of power out of the box (if thermals/whatever allow, a loaded 12900k uses ~240W versus a 5950X using ~120W), hopefully they underclock really well.

[Xyzzy]

https://arstechnica.com/gadgets/2021...a-barn-burner/

[kriesel]

"Does not include free kitten"!

[chalsall]

Originally Posted by kriesel

"Does not include free kitten"!

Please trust me on this. One needs to think seriously about taking on a kitten. Many bites... Much clawing... Ideally, lots of purring...

It's a bit like the Spanish Inquisition. Only, different...

[JWNoctis]

Originally Posted by M344587487

Apparently you can use AVX-512 by disabling the E cores, but it may depend on the motherboard. This video shows the setting present in a bios: https://youtu.be/fhI9tLOg-6I?t=1650


These things use tremendous amounts of power out of the box (if thermals/whatever allow, a loaded 12900k uses ~240W versus a 5950X using ~120W), hopefully they underclock really well.

Interesting read about that here : https://www.anandtech.com/show/17047...d-complexity/2

It remains to be seen whether:

1 - Their AVX-512 instructions would reliably produce correct results in any significant number of cores and chips, as these might not be binned to do so, and
2 - Whether that's actually gonna stay, or be gone in the next stepping, or have a cease-and-desist slapped on it, or something else.

What's about certain is that without AVX-512, Alder Lake is probably going to be slower than Rocket Lake for Prime95, if y-cruncher results are comparable.

[nordi]

Originally Posted by JWNoctis

What's about certain is that without AVX-512, Alder Lake is probably going to be slower than Rocket Lake for Prime95, if y-cruncher results are comparable.

What do you mean? The y-cruncher results show Alder Lake in the lead, especially with DDR-5 RAM.

[Trilo]

Originally Posted by nordi

What do you mean? The y-cruncher results show Alder Lake in the lead, especially with DDR-5 RAM.

DDR5 is quad channel. I assume this helps with these benchmarks especially with y-cruncher being memory bound.