Ryzen 7000X3D Series: A Brief Technical Chat with AMD

[W1zzard]

The 3DV Cache operates at CPU core voltage?​

AMD: The new Ryzen has a CCD with stacked level 3 cache. This creates a balance between clock and cache and allows the chips to achieve maximum performance. CCD 0 has 96 MiB of L3 cache, while CCD 1 only has 32 MiB, but can clock faster.​

The fook are these canned responses? Next time please interview the engineer, not marketing.
Thanks for the article thou.

Good thing is that they answer it in the part about the temperatures "We determined the max. CPU core voltage for safe operation to be slightly lower for Ryzen processors with AMD 3D V-Cache, as those voltages are tied"

 

[Dimitriman]

Aside from the gaming performance, I am mostly happy to see the efficiency on these X3Ds, as AMD managed to bring some serious performance for the SFF crowd without us having to sacrifice volume for extra cooling.

 

[NicklasAPJ]

I have a 7900X3D and absolutely love it. Every Game I play is butter smooth at 4K. Games like Mass Effect 2 look gorgeous at 4K with my panel and I am once again addicted to Gaming. People can say what they want but just looking at the specs for them was why I got the 7900X3D no 7800X3D can do 5.6 Ghz.


Mine pulls about 67 Watts when Gaming and that is about the hardest tasks that my chip does but (some) newer Games do drive your hardware more.

Well you Dont run 5.6Ghz on the cores with 3D cache.. so would be the same as 7800x3D you just have 2 less cores.

Since you game at 4k, the CPU might not make much of a difference so you could go with a 5950X and stay on the same platform. Extra cores, clocks and IPC over the 3900X plus the 5950X is close to the price of a 7800X3D.

But if your budget is high, this is a good time to buy and I would go with the 7950X3D since you do productivity work. Since all the X3D processors are out, I would go ahead and spend the extra money over the non-X3D AM5 parts. I would have bought the 7800X3D over my 7700X but I didn’t want to wait (I only game, no productivity).

By the way, I recommend an Asrock AM5 motherboard over the competition. They seem to most motivated to stay ahead of the game in the AMD space.

He could also just buy a 5800X3D would give him the bedst gaming Performace on AM4.

 

[kapone32]

Well you Dont run 5.6Ghz on the cores with 3D cache.. so would be the same as 7800x3D you just have 2 less cores.


He could also just buy a 5800X3D would give him the bedst gaming Performace on AM4.

If you think a 7800X3D is as fast as my 7900X3D you would be sorely mistaken. People think that all Games only use 1 CCD based on Windows settings but that is only true for some Games. Just think of it this way a 5900X is about as fast as the 5800X3D in terms of FPS but slower in 1% lows. That made the narrative that we wanted V cache on the higher core models. That is exactly what we have gotten and as I said before this is the fastest CPU I have ever felt. It is like combining the snappiness of the 5950x with the smooth feeling of the 5900X but it is in 12 cores and then has Vcache as well. There is also a IGPU with 2 RDNA cores on the package. All with a package that pulls 65 Watts. I could also say that there is also the fact that like the 3000 series chips 1.2 to 1.3 volts is all you need for Uber performance. It's too bad they did not sample them but based on what I have seen they did not need to.

 

[Gucky]

If you think a 7800X3D is as fast as my 7900X3D you would be sorely mistaken. People think that all Games only use 1 CCD based on Windows settings but that is only true for some Games. Just think of it this way a 5900X is about as fast as the 5800X3D in terms of FPS but slower in 1% lows. That made the narrative that we wanted V cache on the higher core models. That is exactly what we have gotten and as I said before this is the fastest CPU I have ever felt. It is like combining the snappiness of the 5950x with the smooth feeling of the 5900X but it is in 12 cores and then has Vcache as well. There is also a IGPU with 2 RDNA cores on the package. All with a package that pulls 65 Watts. I could also say that there is also the fact that like the 3000 series chips 1.2 to 1.3 volts is all you need for Uber performance. It's too bad they did not sample them but based on what I have seen they did not need to.

No the problem is that the 7900X3D has only 6x 3D-Cache Cores. If you have to use more, the latency would increase since the other 6 cores have to access the 3D-Cache as well.
The 7900X3D can feel faster since AMD turned down the 7800X3D's average boostfrequency to make the more expensive CPUs more attractive...

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If you think about efficiency Zen3 runs best around 4,2-4,4Ghz. I have a 5800X3D running 4,42Ghz on all cores. ONE cores uses ~4W power, if HWiNFO is right. ~39W total.
On a 5950X, which I also owned, one core boosted stock with 1.5V to 5.05Ghz and during Cinebench it consumed ~16W of power, according to HWiNFO. ~80W total.
Of course there are some other things inside the CPU that use power, like the IO-die and so on. Measuring one core alone is hard....

As another comparision, my 5800X3D uses 105W power for 4,42Ghz on all cores during Cinebench. The 5950X used 80W for 1-2 Cores on 5,05Ghz. When using all 16 cores it's clocks went down to 3,8Ghz with 142W of power. With a bit of tuning I got it to 4,2Ghz with 142W as well.

With the 5950X tuned down from 5,05Ghz to 4,2Ghz the powerusage from 1-2 core use like in cinebench-single, went down by almost 50%!!! and I lost only 10% points in CB. Imagine that...

The 7000X3Ds run closer so that best efficiency curve then other 7000X CPUs, similar to the example I gave.
Now the problem: Most people want the most amount of performance out of their CPUs, ignoring efficiency. I do not. I don't want a 1kW heater in my room, but I also want a 4k gaming experience as best as possible.
It gets harder to archieve that, If AMD completely locks down the CPU. Yadda yadda 3D-Cache gets damaged... You can lock out CPU overclocking, but still enable undervoltaging...