According to AMD product pages, the upcoming 7950X3D and 7800X3D are Unlocked for Overclocking.

tunejunky

2023-01-25 16:33

geogan:

Well I am not sure who you are replying to or what you mean by "3DCache has zero effect on CCD's", but my point still stands... this new 3D cache is only on one of the CCDs of the new dual CCD CPUs like 7950X3D. This means that all 16 cores of this CPU are no longer equal in performance like they were in previous AMD CPUs like the 5950X . You now have 8 faster cores (16 threads) on 3D cache CCD, and 8 slower cores (16 threads) on normal CCD. So there is a big difference there compared to older CPUs. And probably something they don't want buyers of new 3D cache CPUs to know about.

not accurate afaik. what documentation do you have on different frequencies on differing CCD's? your conclusion is specious regarding (cache-less) CCD's vs. cached CCD's as there are no frequency limitations created by the cache, especially now the cache has it's own regulated power supply heat throttling is a non-issue.

#6096518

tunejunky

2023-01-25 16:34

GarrettL:

I believe AMD is trying to get the best of both worlds. With the design used on the 5800x3d the max speed is limited when compared to the 5800x due to the heat issues with the shared cache. This reduces the performance for games that use primarily one core and is evident in the test results. With the new design AMD is trying to offer the best of both, the huge cache for one CCD for games that benefit at a reduced max frequency and one CCD with the standard cache that can boost to it's max of 5.2GHz-5.6GHZ. Question is, can you manage the heat to allow this to actually happen?

THAT is the question;)

#6096570

geogan

2023-01-25 19:11

tunejunky:

not accurate afaik. what documentation do you have on different frequencies on differing CCD's? your conclusion is specious regarding (cache-less) CCD's vs. cached CCD's as there are no frequency limitations created by the cache, especially now the cache has it's own regulated power supply heat throttling is a non-issue.

well i wasn't talking about frequency differences making the "speed" difference, if that is what you were asking... I meant the extra 3D cache speeding up processes/programs running on one CCD more than the other CCD. Assuming both CCDs run at same frequency. I was not aware the non-cache CCD could be run at higher frequencies now though... that makes things more complicated to figure out - will be almost impossible for any large application to know where it should run best then - very difficult job for Windows scheduler. No idea what "your conclusion is specious" means?!?

#6096614

GarrettL

2023-01-25 21:55

geogan:

well i wasn't talking about frequency differences making the "speed" difference, if that is what you were asking... I meant the extra 3D cache speeding up processes/programs running on one CCD more than the other CCD. Assuming both CCDs run at same frequency. I was not aware the non-cache CCD could be run at higher frequencies now though... that makes things more complicated to figure out - will be almost impossible for any large application to know where it should run best then - impossible job for Windows scheduler. No idea what "your conclusion is specious" means?!?

AMD is working with MS on this very issue. Same growing pains from several years ago. Could also be part of the delay in releasing this cpu.

#6096622

Undying

2023-01-25 23:16

geogan:

well i wasn't talking about frequency differences making the "speed" difference, if that is what you were asking... I meant the extra 3D cache speeding up processes/programs running on one CCD more than the other CCD. Assuming both CCDs run at same frequency. I was not aware the non-cache CCD could be run at higher frequencies now though... that makes things more complicated to figure out - will be almost impossible for any large application to know where it should run best then - very difficult job for Windows scheduler. No idea what "your conclusion is specious" means?!?

Thats why you get 7800x3d with one v-cached ccd.

#6096638

user1

2023-01-26 00:38

geogan:

well i wasn't talking about frequency differences making the "speed" difference, if that is what you were asking... I meant the extra 3D cache speeding up processes/programs running on one CCD more than the other CCD. Assuming both CCDs run at same frequency. I was not aware the non-cache CCD could be run at higher frequencies now though... that makes things more complicated to figure out - will be almost impossible for any large application to know where it should run best then - very difficult job for Windows scheduler. No idea what "your conclusion is specious" means?!?

its really not that complicated the easy solution is a whitelist, also zen 3/4 provides a bunch of profiling abilities for tuning your workload, which do not require root permissions (administrator mode/ring0) so its possible they could use some heuristics from the cpu to dynamically decide which ccd to run an application on. (link for those interested in amd's profiling software https://www.amd.com/en/developer/uprof.html )

#6096681

Astyanax

2023-01-26 07:56

tunejunky:

not accurate afaik. what documentation do you have on different frequencies on differing CCD's? your conclusion is specious regarding (cache-less) CCD's vs. cached CCD's as there are no frequency limitations created by the cache, especially now the cache has it's own regulated power supply heat throttling is a non-issue.

Everything they said is correct.

#6096751

geogan

2023-01-26 12:11

user1:

its really not that complicated the easy solution is a whitelist, also zen 3/4 provides a bunch of profiling abilities for tuning your workload, which do not require root permissions (administrator mode/ring0) so its possible they could use some heuristics from the cpu to dynamically decide which ccd to run an application on. (link for those interested in amd's profiling software https://www.amd.com/en/developer/uprof.html )

Yes it does appear this would be only way... every program would just have to be tested on both CCDs and see which runs faster for that particular "operation". And then marked somehow to always run on faster CCD in future automatically. Messy. Any non-profiles apps would basically just be run randomly. eg. say a Futuremark 3DMark program and benchmark run was not profiled... then it could randomly run on CacheCCD or NonCacheCCD... and get two completely different results for benchmark, one probably much faster than the other. Same with loads of other GPU + CPU intensive "mixed" apps like most games. Also would this be user settable or automatic in OS so no user control? Since this is a very niche CPU there probably wouldn't be much effort to get it right.

#6096761

pegasus1

2023-01-26 12:58

Remember when people said Dual Core CPUs would never work efficiently, this wont even be a problem. if the Ukrainians can work out how to operate US HARM missles from their Mig 29's, im sure the brains at AMD and MS can work this out.

#6096763

Astyanax

2023-01-26 13:05

pegasus1:

Remember when people said Dual Core CPUs would never work efficiently, this wont even be a problem.

I remember that apps often took a performance penalty at the same ipc and clocks on dual core processors vs single core of the same architecture design and feature set. windows itself benefitted mostly.

#6096778

pegasus1

2023-01-26 14:13

Astyanax:

I remember that apps often took a performance penalty at the same ipc and clocks on dual core processors vs single core of the same architecture design and feature set. windows itself benefitted mostly.

Yes but before they actually came to be, when they were in the conceptual stage. Humanity always finds a way and necessity is the mother of invention. Humans have a history steeped in making the impossible possible.

#6096787

fantaskarsef

2023-01-26 14:42

Espionage724:

Is there a 3D CPU without any CCD nonsense? Or any Ryzen CPU with only a single CCD?

The CPUs with a single CCD and 3D cache are the 5800X3D, and the 7800X3D afaik

#6096790

tunejunky

2023-01-26 14:44

geogan:

well i wasn't talking about frequency differences making the "speed" difference, if that is what you were asking... I meant the extra 3D cache speeding up processes/programs running on one CCD more than the other CCD. Assuming both CCDs run at same frequency. I was not aware the non-cache CCD could be run at higher frequencies now though... that makes things more complicated to figure out - will be almost impossible for any large application to know where it should run best then - very difficult job for Windows scheduler. No idea what "your conclusion is specious" means?!?

1) "faster" = frequency as that's the literal meaning and usage. 2) the operation of processes running from 3D CCDs are not typically the same as processes run from another CCD (i.e. gaming) so any differential would most likely be found in productivity applications where the difference does not amount to much. 3) synthetic benches will highlight any such difference, but the result is not useful in RL. 4) most importantly, all of the concerns regarding performance are belied by Epyc processors in the real world handling far more complicated work. these "concerns" have never surfaced in the Pro IT Cloud.

#6097249

Dribble

2023-01-27 17:35

pegasus1:

Remember when people said Dual Core CPUs would never work efficiently, this wont even be a problem. if the Ukrainians can work out how to operate US HARM missles from their Mig 29's, im sure the brains at AMD and MS can work this out.

It's a question of incentive - every cpu was going to be multi-core so devs had to make it work. Ukraine really needs those missiles to work, they will save Ukrainian lives and help them win the war. A tiny number of people will end up with cpu's that have this behaviour, and the extra performance (a few % probably) isn't much. There just isn't enough payback to put much effort in.

#6097286

pegasus1

2023-01-27 18:38

Dribble:

It's a question of incentive - every cpu was going to be multi-core so devs had to make it work. Ukraine really needs those missiles to work, they will save Ukrainian lives and help them win the war. A tiny number of people will end up with cpu's that have this behaviour, and the extra performance (a few % probably) isn't much. There just isn't enough payback to put much effort in.

Necessity is the mother of invention.

#6097287

user1

2023-01-27 18:44

geogan:

Yes it does appear this would be only way... every program would just have to be tested on both CCDs and see which runs faster for that particular "operation". And then marked somehow to always run on faster CCD in future automatically. Messy. Any non-profiles apps would basically just be run randomly. eg. say a Futuremark 3DMark program and benchmark run was not profiled... then it could randomly run on CacheCCD or NonCacheCCD... and get two completely different results for benchmark, one probably much faster than the other. Same with loads of other GPU + CPU intensive "mixed" apps like most games. Also would this be user settable or automatic in OS so no user control? Since this is a very niche CPU there probably wouldn't be much effort to get it right.

I think you're making a bit of a mountain out of a mole hill so to speak, whitelists are pretty easy , since you litterally just have to run the application twice, would take a single person maybe a week or 2 to test all of the most popular games. secondly if they were to use heuristics its probably not very difficult , I'd imagine even just checking l3 occupancy and or hit rate would be enough, ie, "this application doesn't hit the l3 cache very often --> move to ccd 1" , the part where it could get messy is if an application can use more than 16 threads, but that's probably an edge case for the vast majority of users.

#6098871

geogan

2023-02-01 18:16

user1:

I think you're making a bit of a mountain out of a mole hill so to speak, whitelists are pretty easy , since you litterally just have to run the application twice.

Maybe so. But will end user be able to do this for their own applications that were not checked and tested by this magical person who is going to test every application in existence?

#6098878

WhiteLightning

Moderator

2023-02-01 18:27

https://cdn.videocardz.com/1/2023/02/7003D-HERO-1-2048x888.jpg Feb 28th

#6098905

Horus-Anhur

2023-02-01 19:06

[youtube=FLxH9ivPWUI]

#6098935

user1

2023-02-01 20:21

pricing looks pretty good , thought it would be more expensive.

geogan:

Maybe so. But will end user be able to do this for their own applications that were not checked and tested by this magical person who is going to test every application in existence?

obviously the user can do something about this themselves even if amd doesn't provide an easy switch, as simple as setting core affinity. I gonna go out on a limb and say that 99.9% of users will not notice , since the performance of zen4 is already really good. real world professional workloads are heavily multithreaded. so what does that leave , maybe the lame mp3 encoder , spreadsheets, word processors? obscure games might suffer, but you'll probably have more than sufficient performance anyway. Does this user, that mostly uses applications not on the whitelist, and is adversely effected by a performance regression, even exist? I'm guessing there is maybe 5 people world wide that could hypothetically purchase this product and be unsatisfied with it specifically for this reason.