July 2024 Update on Instability Reports on Intel Core 13th/14th Gen Desktop CPUs

https://www.youtube.com/watch?v=yYfBxmBfq7k

Keep in mind that the L2 cache is the last level cache for the E cores, and is shared by the entire cluster of four E cores. (One of the two clusters connects to the ring bus and shares the main L3, the other goes directly to main memory)

I'm guessing Intel can shut down VccCore entirely (which wipes every other cache), while keeping just enough voltage to maintain the E core L2 cache. By keeping valid data in L2, they can resume execution on an E core much quicker.

And as long as the reason for waking is a small periodic housekeeping task, they don't even need to wake up main memory. All the data fits in the 2MB of L2 cache. This makes resuming even faster and saves even more power. Finally, quick resumes allow the task to complete quicker and shut down VccCore again, which saves even more power.

This extreme level of power saving isn't really useful for desktops, but very useful for laptops and tablets. BTW, I'm not talking about a sleep mode here, the CPU will ideally be able to enter this mode anytime there is no tasks to run for at least the next millisecond, so it can save power even when the user is actively using the system.

or at least... maybe on the CPU side they were no-drama. Other than C2000/C3000. Granted the powervr graphics on the atoms way back did suck... and meltdown... and avx-512 being rolled back... /phillip j fry counting on his fingers

maybe "blue-chip coded" is a better way to express it ig

but like, there is a notable decline in the quality of execution of intel overall, pretty much across the board, and cpu was always their core vertical, right? That was their business redoubt. intel is blue chip chips, especially CPUs. And now it's falling - really it's been falling for a while. Meltdown I can generally excuse (yes, shush), nobody appreciated sidechannels back then even if they were theoretically known. C2000/C3000 is another fuckup. yeah it's the super-io/serial bus controller... technically not their IP but it happens to be in a critical path, on their node, killing their processor. They fucked up the validation there, evidently.

I-225V had three steppings and I-226V is still not fully fixed (windows/linux have just turned off the EEE/802.11az feature instead). Puma was a god damned mess.

Sapphire rapids was late, still a huge mess, and actually the -W platform had not only insane power draw, but also insaner transients. 750W average, spiking up to 1500W under load, with pretty steep holdup requirements. And actually that was locked behind a "water cooled" bios option, the processor just "refused to all-core turbo" otherwise. And Intel didn't wanna actually say that the "water cooled" behavior was the spec or intentional turbo limits etc. In hindsight hmmm, that all took a bit of a different tone, didn't it?

Supposedly there is going to be a SPR-W refresh with a new stepping to fix this... emerald rapids is also very power-hungry and there were some unconfirmed murmurs suggesting it might have the same crash problems.

(yes, yes, please just listen to the guest here.) https://www.youtube.com/watch?v=_HJu5xt43iQ&t=3603s

https://wccftech.com/intel-xeon-w-3500-w-2500-sapphire-rapid...

Intel's in some real danger especially with AMD ascendant like this. Like it doesn't take very long of this real damage to customers etc and that "we're blue-chip!" thing will cease to be, and that is the last prop keeping intel's finances above the water here. Sure, it will take a while to fully wind down but... this is a great example of how intel's fuckups are driving their clients literally into the arms of the competition. A month or two ago, Asrock Rack didn't give a shit about the B650-2L2T or whatever. Guess what? Now Epyc Mini exists and oems are going to be paying attention to that. Oops.

For any named product (such as Raptor Lake) intel only make 1-3 unique silicon dies. Any product in the Alder Lake only had two dies, 8P+8E and 6P+0E [1]. Every single SKU comes from those two dies, if it has E cores, it's the 8P+8E die. Which means Alder Lake-N is actually the 8P+8E dies with all the P cores disabled.

The laptop versions, Alder Lake-P (20w) and Alder Lake-U (9 and 15w) are also the 8P+8E die, they couldn't use the 6P+0E die, because it has no E cores at all.

Raptor Lake is only one die with 8 P cores and 16 E cores, which they sell as every i9 and i7, along with the two top i5 designs. In the 13th generation, the remaining i5s are the Alder Lake 8P+8E die and the i3s are all Alder Lake 6P+0E dies.

The manufacturing defects aren't binary, it's not a simple pass/fail. It's all very analog: Some dies are simply able to reach higher clock speeds, or use more or less power. They test every single die and bin it based on its capabilities. The ones with the best power consumption go to the P and U SKUs. The ones which can reach the highest clock speeds are labeled as 13900KS, dies which just miss that get sold as 13900K, the rest get spread over all remaining SKUs based on their capabilities.

Intel couldn't decide to exclusively make 13900KS dies if they wanted to, because they are simply the top 0.1% of dies. They are forced to make 1000 dies, use the best one and sell the rest as lower SKUs.

[1] Wikichip has photos of the two dies: https://en.wikichip.org/wiki/intel/microarchitectures/alder_...