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AMD releases a new flagship CPU for consumer market with 128M of L3 Cache

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Re: AMD releases a new flagship CPU for consumer market with 128M of L3 Cache

#121

Post by Firther »

Prunkton wrote: post #90
pella wrote: post #13

"AMD Ryzen 9 7950X3D Linux Performance" https://www.phoronix.com/review/amd-ryzen9-7950x3d-linux "AMD Ryzen 9 7950X3D Desktop CPU Review Roundup" https://videocardz.com/150677/amd-ryzen-9-7950x3d-desktop-cp...

the Linux test leaves me quiet confused how to pick my next linux gaming cpu. On the one hand side Gamers Nexus is making a point [0] (there are on/off performance charts later in the video) why it is super important to install the latest windows drivers + special windows gaming software to make use of the heterogeneous architecture. On the other hand side the linux tests are much better then I would expected since i…

It's not quite the same out of the box experience (after making sure you have the latest chipset drivers, use the balanced power plan and NOT the performance plan, and have Xbox Game Bar..), but it's possible to force certain processes and executables to run on specific CPU cores in Linux using taskset and verify that they're running on the correct cores. It will be a little tedious if you play a lot of games on Steam as you'll inevitably run into games that use proton and others that use native binaries, but there's nothing that should prevent you from being able to manually schedule games/programs that need the extra cache onto the cores that have the extra cache.

Re: AMD releases a new flagship CPU for consumer market with 128M of L3 Cache

#122

Post by bee_rider »

londons_explore wrote: post #110

Lots of software could run in just 128MiB, especially if it could page stuff out to ssd. CPU's usually have a cache-as-ram mode that can enable this. Does this mean that systems where you can hot swap all the ram at once will be possible?

It doesn’t feel that long ago, that computers would have hundreds of megabytes of RAM. I remember it — my back is a little sore, but I’ve still got all my hair.

Re: AMD releases a new flagship CPU for consumer market with 128M of L3 Cache

#123

Post by bee_rider »

jeffbee wrote: post #39
sct202 wrote: post #20

Wow basically the same pref as a 13900k but so much less power usage in the aggregated tests. Apps : 79w vs 169w Games : 56w vs 143w

In my experience you can tune the i9-13900K way down on power and barely notice or not at all. I wouldn’t be surprised if these benchmarks came out the same way on the Intel side with power caps set at 125W.

I feel like I must be asking a dumb question, because it is a pretty obvious one. But would it be better to just buy a lower-performing, lower-cost chip in that case? Does the silicon lottery they results in an i9 also result in better performance per watt?

Re: AMD releases a new flagship CPU for consumer market with 128M of L3 Cache

#124

Post by MrFoof »

goosedragons wrote: post #67
likeclockwork wrote: post #56

Earlier quoted context omitted.

What driver is responsible for assigning specific games to specific CPU CCDs? Is this a real thing? Is it available on Linux? Or am I sticking with Intel?

It's the CPU scheduler. You can easily avoid this by just not buying an X3D variant. Recent Intel CPUs can have the same problem where processes get assigned to the efficiency cores instead of performance cores if the right scheduler isn't used (like by using Windows 10 or an old Linux distro without explicit support)

This is a very short-sighted approach. MCM is coming to Intel too. Moreover, hybrid architectures are coming to AMD with Zen 5. I've historically argued that Zen 4 X3D is a bit of a "beta test" prior to Zen 5, where scheduler improvements are going to be far more impactful when AMD moves to a hybrid architecture like Intel did with their 12th gen. Zen 4 X3D is the time to learn things and fix initial mistakes, before Zen 5 is much more of a prime time, especially in the data center.

This is going to require scheduler improvements not only from the microprocessor manufacturers, but the Windows, BSD and Linux kernels. There is going to be non-stop improvements to maximize the architectures.

Heck, Linux has an entirely new scheduler (https://www.phoronix.com/news/Nest-Linux-Scheduling-Warm-Cor...) being proposed that not only improves performance, but power efficiency, simply by keeping "hot cores hot", because the impact is far more relevant today than the last time the kernel's scheduler was seriously revisited. It's not like multi-core architecture is new either, it's just that the core count increase is going up so fast the impact keeps getting larger.

-- -----

Although I'd generally agree with a sentiment "don't bet on future things you don't have today" the reality is software is always catching up to hardware. Moreover, for major changes to CPU design, they don't YOLO out perfection in one pass -- it takes a while, by many large groups, over years, to eke every scrap of performance out of it.

NAND is a great example of this. The vast increase in IO has hamstrung a lot of stuff. Linux is straight up slamming into IO scheduler limits (NT kernel even more so) at a level that can be achieved by normal human beings, not big companies. That isn't because NAND is bad or flawed. It's because a near future where that kind of performance was possible wasn't considered in the IO scheduler's design.

In the case of Factorio, I'd bet good money that of ALL the game devs out there, the Factorio devs will be jumping all over this one to ensure it's resolved quickly.

Re: AMD releases a new flagship CPU for consumer market with 128M of L3 Cache

#125

Post by [deleted] »

sliken wrote: post #93
HelixEndeavor wrote: post #68

Earlier quoted context omitted.

So presumably a bug that can be fixed by either AMD updating their optimizer, Factorio updating to work better with it, or both?

Or just buy the X3D that have cache on each CCD instead of half of them.

[deleted]

Re: AMD releases a new flagship CPU for consumer market with 128M of L3 Cache

#126

Post by bitL »

Tuna-Fish wrote: post #95
sliken wrote: post #93

Earlier quoted context omitted.

Or just buy the X3D that have cache on each CCD instead of half of them.

More precisely, buy the X3D that has only one CCD. There is currently no consumer model with 2 CCDs and X3D on both of them.

Can't you disable the CCD without the 3D cache? I remember being able to disable 3 CCDs on my Threadripper using Ryzen Master for gaming.

Re: AMD releases a new flagship CPU for consumer market with 128M of L3 Cache

#128

Post by jeffbee »

bee_rider wrote: post #123
jeffbee wrote: post #39

Earlier quoted context omitted.

In my experience you can tune the i9-13900K way down on power and barely notice or not at all. I wouldn’t be surprised if these benchmarks came out the same way on the Intel side with power caps set at 125W.

I feel like I must be asking a dumb question, because it is a pretty obvious one. But would it be better to just buy a lower-performing, lower-cost chip in that case? Does the silicon lottery they results in an i9 also result in better performance per watt?

Yeah, it definitely depends on your use case. In my opinion the only reason to get the K or KS SKU is that you want, and are sensitive to, the extra speed bins you get on the 2 magic P-cores. The KS is a full 10% faster on single-threaded, compute-bound workloads. That's like importing the next generation CPU from the future and it is worth it for some use cases. Even with 1 core running at 6GHz you won't blow out a 125W power cap.

Re: AMD releases a new flagship CPU for consumer market with 128M of L3 Cache

#129

Post by moremetadata »

londons_explore wrote: post #110

Lots of software could run in just 128MiB, especially if it could page stuff out to ssd. CPU's usually have a cache-as-ram mode that can enable this. Does this mean that systems where you can hot swap all the ram at once will be possible?

I've always found L2 cache delivered better performance for the work I do.
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