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Intel completely disables AVX-512 on Alder Lake after all

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Re: Intel completely disables AVX-512 on Alder Lake after all

#51

Post by Fnoord »

jacquesm wrote: post #30
Fnoord wrote: post #20

Earlier quoted context omitted.

Nvidia do the same with disabling passthrough on consumer GPUs (gotta upsell Quatro). However I would say avoiding Intel completely is unnecessary. They're a good FOSS citizen when it boils to things like WLAN and GPU. Its just that with AMD, you can hardly go wrong on CPU and GPU side. Especially on Linux.

Yes, but with NVidia at least they get it right and do it prior to benchmarking and selling into the retail channel, rather than the other way around. And they - rightly - get plenty of flak for it.

Nvidia is great for Windows.

As soon as you want to use Linux or macOS or Proxmox or anything, prepare for trouble. Its just not a FOSS-friendly company.

Even on the Nvidia Shield TV (a great bang for the buck) they added commercials in the new UI. Though one might attribute that to Google, it is the only Nvidia device I bought past 5 years. And the only one which got a feature downgrade (or upgrade with a feature I don't want/like).

With regards to Intel I remember my 4770k not having a specific feature (IIRC for hardware virtualization) which all non-k series had. And I found that out too late.

Re: Intel completely disables AVX-512 on Alder Lake after all

#52

Post by zokier »

qayxc wrote: post #34
marcan_42 wrote: post #28

Earlier quoted context omitted.

You can only upgrade microcode on any given boot, not downgrade it. Therefore, if the BIOS has already upgraded your microcode for you on boot, you can't undo that from the OS.

The BIOS doesn't upgrade microcode - the OS does. During boot there's usually no network connectivity, so how would the BIOS even know of an update, let alone acquire it?

The CPU can update its microcode before executing BIOS, the BIOS can do its updates, and then the OS can do its stuff. It's all described in https://www.intel.com/content/www/us/en/developer/articles/t...

Re: Intel completely disables AVX-512 on Alder Lake after all

#53

Post by philliphaydon »

Fnoord wrote: post #42
flatiron wrote: post #33

Earlier quoted context omitted.

I’m waiting for amd to do TB4 so I can get a ryzen framework laptop.

Yeah, AMD Ryzen Framework laptop would be amazing. (Would also have ECC support?) They'd have to license TB from Intel. I don't know about TB4, but TB3 is royalty-free, just gotta pass a certification. TB3 or better would be great for eGPUs in general. Not sure I personally would need TB4. Also, I wonder if Framework would be usable with say Proxmox and macOS (or 'native' Hackintosh?)

The ryzen 6000 series for laptops will support usb 4 with tb3.

What does tb4 offer over 3?

Re: Intel completely disables AVX-512 on Alder Lake after all

#54

Post by [deleted] »

qayxc wrote: post #34
marcan_42 wrote: post #28

Earlier quoted context omitted.

You can only upgrade microcode on any given boot, not downgrade it. Therefore, if the BIOS has already upgraded your microcode for you on boot, you can't undo that from the OS.

The BIOS doesn't upgrade microcode - the OS does. During boot there's usually no network connectivity, so how would the BIOS even know of an update, let alone acquire it?

[deleted]

Re: Intel completely disables AVX-512 on Alder Lake after all

#55

Post by jsheard »

Croftengea wrote: post #40
codeflo wrote: post #11

If all of this was planned (and I’m not saying it is), that would have been very clever. It would work like this: 1. You “accidentally forget” to disable the feature in hardware. Given how competitive the market is, motherboard manufacturers can be relied upon to enable it in their “1337 OVERCLOCKZ” mode. No conspiracy is needed. 2. You “tolerate” this practice just long enough to win the critical initial wave of rev…

> just long enough to win the critical initial wave of reviews and benchmarks. Is the average set of tests by, say, LTT or THG influenced by presence of these instructions? (not being snarky, I really don't know).

Even if a reviewers test suite does benefit from AVX512, it's unlikely that their Alder Lake reviews would actually be swung by it because AVX512 was always disabled in the standard configuration with all of the CPU cores enabled. Enabling AVX512 required disabling the efficiency cores altogether, and running with just the performance cores.

It might have mattered with the lower end Alder Lake parts that only have performance cores, but those haven't been released or reviewed yet.

Re: Intel completely disables AVX-512 on Alder Lake after all

#56

Post by bravo22 »

zinekeller wrote: post #19
codeflo wrote: post #11

If all of this was planned (and I’m not saying it is), that would have been very clever. It would work like this: 1. You “accidentally forget” to disable the feature in hardware. Given how competitive the market is, motherboard manufacturers can be relied upon to enable it in their “1337 OVERCLOCKZ” mode. No conspiracy is needed. 2. You “tolerate” this practice just long enough to win the critical initial wave of rev…

I'll be honest, this looks to be a simple mistake. Cutting AVX-512 literally (meaning in hardware) requires actual staff doing that cut plus it'll increase turnaround times, plus the efficiency cores don't have it. Unlike "let's bin perfectly functional processors into a lower-cored product", this is economically not logical for Intel, which often is the closest from the truth.

"cuts" are almost always fuses that are blown by ATEs during wafer manufacturing or post packaging tests. It is a bit flip.

There is no extra cost.

Re: Intel completely disables AVX-512 on Alder Lake after all

#57

Post by antman »

gambiting wrote: post #7
christkv wrote: post #2

Is this not the definition of bait and switch? How can this not end up in a lawsuit and investigation from regulatory bodies ?

It was never advertised, and Intel very specifically said AVX-512 instructions will not be available. Some motherboard manufacturers made them available anyway, now Intel is fixing that. It's like buying a car with an advertised speed limiter of 155mph, then finding that actually it can go 170mph, and then the manufacturer fixes the speed limiter with a software update. Yes we know the car could go faster, but the sp…

Good example. It’s like buying a car and finding out it has a nice radio that was not advertised. After a few months the car dealership sends someone to break into the car and rip it off. Fair enough since it wasn’t advertised, right?

Re: Intel completely disables AVX-512 on Alder Lake after all

#59

Post by nullify88 »

marcan_42 wrote: post #26
pantalaimon wrote: post #16

Since Linux loads the microcode on it's own, can this be used to apply an old microcode or is there a prevention against downgrading the version?

I'm pretty sure downgrades are blocked. You need to hack the BIOS so the (volatile) upgrade never happens on boot.

I wouldnt call it hacking. If you can find or backup the bios image for your motherboard, you can replace the microcode in it and reflash. Bios images are modular and the microcode is a replacable component.
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