AMD releases a new flagship CPU for consumer market with 128M of L3 Cache • Hacker News Board

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

#81

Post by goosedragons » Mon, Feb 27, 2023, 4:52 PM UTC

kllrnohj wrote: post #75

goosedragons wrote: post #67

Earlier quoted context omitted.

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)

Or buy an X3D that's homogeneous, like the 5800X3D or upcoming 7800X3D. I have no idea why AMD made the 7950X3D be this weird 50/50 split. Why not make both CCDs have 3D V-cache and make it the true halo part it should be? Then cut costs with the 7900X3D?

Because the added 3D V-cache increases heat. That's also why the X3D variants have lower clocks than the non-X3D versions. Two CCDs with V-cache is apparently too hot.

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

#82

Post by thfuran » Mon, Feb 27, 2023, 4:54 PM UTC

varispeed wrote: post #63

Have you noticed how AMD and Intel just do tiny steps, sometimes even not worth writing about when it comes to innovation? It's always either AMD matching the new Intel CPU of other way around - it's never about eg. completely crushing Intel. This is the problem of late stage capitalism, where both companies are owned by the same large investment funds and they use their power to ensure neither company could eat too…

No, it's the problem of cpu design being really fucking hard.

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

#83

Post by jrmg » Mon, Feb 27, 2023, 4:55 PM UTC

shock-value wrote: post #38

perihelions wrote: post #33

AnandTech sees some intriguing regressions on certain benchmarks, https://www.anandtech.com/show/18747/the-amd-ryzen-9-7950x3d... ( "CPU Benchmark Performance: Simulation" ) Worst is Factorio, which is down -47% against the 5800X3D (a previous-generation CPU that also uses stacked L3 cache), on the benchmark "10K trains". Wonder what's going on there? - "We would have expected higher performance in our Factorio bench…

[flagged]

Is there a point to going beyond 60 updates/s in Factorio? Because if not the system seems to be doing the correct thing and using less power. I hope AMD isn’t causing higher power usage for all users just to game some benchmarks!

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

#84

Post by moffkalast » Mon, Feb 27, 2023, 4:56 PM UTC

HelixEndeavor wrote: post #68

drewg123 wrote: post #45

Earlier quoted context omitted.

When they manually forced it onto the CCD with 3D-Vcache, they saw a 100% speedup: " As we can see in our Factorio benchmark, we saw massive gains of over 100% when forcing the Ryzen 9 7950X3D to use the CCD with the 3D V-Cache as opposed to letting AMD's PPM Provisioning and 3D V-Cache Optimizer drivers do their thing automatically. "

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

If it's a problem for Factorio it's also a problem for others, so definitely something to fix on the AMD side.

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

#85

Post by caycep » Mon, Feb 27, 2023, 4:57 PM UTC

alyandon wrote: post #21

Scandiravian wrote: post #8

I wish they'd included the results of the undervolted 7950x in the graphs (aka ECO mode) It's sad that performance benchmarks have made market conditions where the gain of 5% performance is somehow worth 20%-30% extra power consumption (and the noise that follows from that)

I just disable PBO on my 3900X - you are 100% correct that an extra 5% performance is not worth the extra 30% power draw/heat.

This is the same as AMD "Eco Mode"?

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

#86

Post by cma » Mon, Feb 27, 2023, 4:57 PM UTC

brundolf wrote: post #59

Silly question: what constrains cache sizes? What prevents just making them bigger and bigger?

SRAM burns more power and uses more die space than DRAM

Some do make them bigger and bigger, like the whole-die cerebras AI chip.

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

#87

Post by moffkalast » Mon, Feb 27, 2023, 4:57 PM UTC

pizza234 wrote: post #65

brundolf wrote: post #59

Silly question: what constrains cache sizes? What prevents just making them bigger and bigger?

AFAIK, power and speed. There's an interesting paper on this topic: [Cache Design Trade-offs for Power and Performance Optimization: A Case Study]( http://iacoma.cs.uiuc.edu/CS497/LP5a.pdf ).

"With power and speed one can achieve many things."

- Jeremy Clarkson

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

#88

Post by bombcar » Mon, Feb 27, 2023, 4:58 PM UTC

ChuckNorris89 wrote: post #64

mabbo wrote: post #37

Earlier quoted context omitted.

Is it? Have a look at this article from 2002: > With the cuts, the wholesale cost of a 733-MHz Pentium III drops 3 percent, from $776 to $754, while the 700-MHz version drops 3 percent from $754 to $733 in volume. https://www.cnet.com/culture/intel-cuts-pentium-iii-prices-1... $754 in today's dollars is over $1250. Cutting edge processors are cheaper than they were 20 years ago.

Indeed. People forget that flagship Intel Extreme Edition or AMD Athlon FX chips from ~17 years ago were retailing for over 1000$ in the money of that time. In today's roubles they would be around 1500$ adjusted for inflation. Ouch! Today 750$ for a flagship CPU that buys you the best possible compute in the consumer space is not a bad deal at all. It's never been a better time for X86 CPU shopping. You most likely d…

Yeah, the "top of the line" processors were often insanely priced (and some were not available for love or money, basically paper launches only available to those with connections).

https://www.redhill.net.au/iu.php is a good read down memory lane about those things, even as far back as the 286 you had it. Sometimes very rarely and almost as a mistake the "best bang for the buck" processor AND the "fastest in the world" would overlap.

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

#89

Post by convolvatron » Mon, Feb 27, 2023, 4:59 PM UTC

brundolf wrote: post #59

Silly question: what constrains cache sizes? What prevents just making them bigger and bigger?

suprised there are three answers that dont mention area. the larger a die is the more expensive it is to produce, since the chance of getting a defect goes up. wafer-scale integration works by providing sufficient redundancy and/or routing to avoid damaged areas, but that too has a cost.

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

#90

Post by Prunkton » Mon, Feb 27, 2023, 5:01 PM UTC

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 it can not know out of the box what core to pick. Maybe the 50/50 pick is good enough for how the charts look...

[0]: https://youtu.be/9gCzXdLmjPY?t=350