Tuesday, April 18th 2023
Ryzen 7000X3D Series: A Brief Technical Chat with AMD
Earlier this month, AMD wrapped up the launch of its incredible Ryzen 7000X3D processor series, which storms the company's gaming performance competitiveness against Intel back to the top, setting it up for the crucial Spring-Summer season, when PC gamers tend to upgrade and play the latest games. The 3D Vertical Cache memory deployed on the Ryzen 9 7950X3D, 7900X3D, and Ryzen 7 7800X3D, supercharges the gaming performance of these processors, and our testing has shown that the 7800X3D is all that an elite gaming PC build needs if all you're doing is playing games with some domestic productivity on the side; whereas the 7950X3D is for those into heavy content creation and application workloads besides gaming, which means AMD levels up to Intel on both fronts.
We have extensively covered the technical aspects of what 3D Vertical Cache is, and how it works, in our reviews of the 7950X3D and 7800X3D. It is a fast 64 MB slice of SRAM cache stacked on top of the 32 MB on-die L3 cache of "Zen 4" chiplets, which extends the L3 cache size to 96 MB. This has a profound impact on gaming workloads, as the CPU cores have more amount of game data at much lower latency than DRAM. As part of our coverage of the Ryzen 7000X3D processor series, we had the opportunity to interview AMD on some of the technical aspects of Ryzen 7000X3D processor series. We also took the opportunity to ask a few general questions about the Ryzen 7000 desktop processor series itself. You can also catch our interview with Robert Hallock, the former technical marketing head, for some additional questions that you may find relevant.
TechPowerUp (TPU): Does the 7900X3D have a 6+6 core CCD configuration, or 8+4?
AMD: While the Ryzen 9 7950X3D processor has 2 CCDs, each of them with 8 cores, the Ryzen 9 7900X3D processor has 2 CCDs with 6 cores. The Ryzen 7 7800X3D processor owns 1 CCD with 8 cores.
The Ryzen 9 7900X3D processor offers two CCDs with the same L3 cache configuration as the Ryzen 9 7950X3D processor. But be aware - the core configuration differs: The CCD of the 7900X3D processor has six cores enabled, however one with the same 64 MB L3 cache added, or, 10.7 MB of L3 cache per core, as the 7950X3D processor CCD with AMD 3D V-Cache.
TPU: 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.
TPU: Is the cache die the same design as the one used on 5800X3D? If not, anything you could share on what's new?
AMD: At a silicon level, the AMD 3D V-Cache technology on Ryzen 7000 X3D processor is largely the same technology as was used on Ryzen 5800X3D processors. The most significant improvements are in the firmware and product development activities, through which we have now enabled 2-CCD versions, PBO, and Curve Optimizer functionality.
TPU: Should overclockers be careful with how much voltage they apply on the X3D SKUs? (versus what's safe on the non-X3D SKUs)
AMD: The safe voltage range is the one programmed from the factory, which is automatically controlled by the firmware underlying the power management and boost algorithms. PBO, and Curve Optimizer functionality are enabled, for this generation. Users can fine tune via the BIOS or use Ryzen Master.
TPU: Is the IGP able to access the 3DV Cache?
AMD: AMD Ryzen 7000 CPUs have the same basic graphics engine with 2 AMD RDNA 2 CU's. The built-in graphics is meant to provide basic display-out capabilities for troubleshooting, as well as enough performance for watching videos and doing basic office tasks. The built-in graphics resides on the I/O die and is a self-contained unit with its own L2 cache. It does not access the L3 cache on any of the compute dies.
Can we expect BIOS-level scheduler toggles such as "prefer cache," and "prefer frequency" to be incorporated to Ryzen Master? Able to they apply on-the-fly without restart?
AMD: Currently, as you may know, the CCD/Thread optimizing for AMD 3D V-Cache is done via the OS and Microsoft's Xbox Game Bar, when gaming. We can see if there is a desire to be able to manually toggle the CCD, besides disabling one via Ryzen Master or in the BIOS.
TPU: Can you please detail the technical reason behind lowering the Tjmax value to 89 Celsius, down from 95C?
AMD: The AMD 3D V-Cache DIE requires certain power and voltage. 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. As a result you see our Ryzen 7000 Series processors with AMD 3D V-Cache have an official TDP of 120 W, instead of 170 W for some of the non-3D V-Cache versions. This is by design and also means we could run a lower TjMax.
With that reduced TDP we do see many of the 3rd party coolers that are confirmed to be compatible and working well with AMD Ryzen 7000 Series processors, to be work great on Ryzen 7000 processors with AMD 3D V-Cache.
TPU: What happens if I run a game in the foreground and a renderer in the background? What if I alt+tab and switch away from the game?
AMD: The AMD 3D V-Cache CCD is utilized for any 3D application that is running. Any other workloads are scheduled to be executed by the second CCD (should the CPU in question feature two CCDs). When performing a combination of these workloads, both CCDs will be utilized accordingly.
TPU: How does the PPM Driver detect a game? Just based on MS Game Bar detection?
AMD: Essentially when a Ryzen 7000X3D processor goes into "game mode", it's because Xbox game bar detects a game is running and puts the workload on the CCD with the AMD 3DV-cache technology.
TPU: The 7800X3D will run at optimum performance without any Performance Optimizer Driver / PPM Driver / Game Bar?
AMD: We always recommend to follow our teams instructions when testing AMD Processors. This includes installing the correct AMD Chipset Software as well as ensuring you are running on an optimized OS, for testing AMD 3D V-Cache technology. With a single CCD product with AMD 3D V-Cache technology you will find that a workload capable of benefiting from higher levels of L3 cache, will automatically see optimized performance, when the basic steps are followed.
TPU: In our testing, we noticed some outliers to the 3DV cache optimization. Is AMD identifying and optimizing for these games? Will we see AMD Chipset Software receive more frequent updates for game optimizations going forward?
AMD: While some games highly benefit from having more L3 cache, other may see less of a performance jump. Similar to when AMD first introduced Ryzen and Threadripper CPUs, with Chiplet design, and as we introduced the Ryzen 7 5800X3D processor, we are partnering closely with Microsoft to help optimize the built in thread scheduler in Windows for AMD Ryzen & Threadripper processors to ensure full benefit from our technologies. Additionally, we continue to work closely with Game Developers to ensure game threads are optimally scheduled to take advantage of the large AMD 3D V-Cache technology available on Ryzen 7000X3D processors.
Catch the TechPowerUp Reviews of the Ryzen 9 7950X3D | Ryzen 7 7800X3D | Ryzen 9 7950X3D with non-X3D CCD Disabled
We have extensively covered the technical aspects of what 3D Vertical Cache is, and how it works, in our reviews of the 7950X3D and 7800X3D. It is a fast 64 MB slice of SRAM cache stacked on top of the 32 MB on-die L3 cache of "Zen 4" chiplets, which extends the L3 cache size to 96 MB. This has a profound impact on gaming workloads, as the CPU cores have more amount of game data at much lower latency than DRAM. As part of our coverage of the Ryzen 7000X3D processor series, we had the opportunity to interview AMD on some of the technical aspects of Ryzen 7000X3D processor series. We also took the opportunity to ask a few general questions about the Ryzen 7000 desktop processor series itself. You can also catch our interview with Robert Hallock, the former technical marketing head, for some additional questions that you may find relevant.
AMD: While the Ryzen 9 7950X3D processor has 2 CCDs, each of them with 8 cores, the Ryzen 9 7900X3D processor has 2 CCDs with 6 cores. The Ryzen 7 7800X3D processor owns 1 CCD with 8 cores.
The Ryzen 9 7900X3D processor offers two CCDs with the same L3 cache configuration as the Ryzen 9 7950X3D processor. But be aware - the core configuration differs: The CCD of the 7900X3D processor has six cores enabled, however one with the same 64 MB L3 cache added, or, 10.7 MB of L3 cache per core, as the 7950X3D processor CCD with AMD 3D V-Cache.
TPU: 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.
TPU: Is the cache die the same design as the one used on 5800X3D? If not, anything you could share on what's new?
AMD: At a silicon level, the AMD 3D V-Cache technology on Ryzen 7000 X3D processor is largely the same technology as was used on Ryzen 5800X3D processors. The most significant improvements are in the firmware and product development activities, through which we have now enabled 2-CCD versions, PBO, and Curve Optimizer functionality.
TPU: Should overclockers be careful with how much voltage they apply on the X3D SKUs? (versus what's safe on the non-X3D SKUs)
AMD: The safe voltage range is the one programmed from the factory, which is automatically controlled by the firmware underlying the power management and boost algorithms. PBO, and Curve Optimizer functionality are enabled, for this generation. Users can fine tune via the BIOS or use Ryzen Master.
TPU: Is the IGP able to access the 3DV Cache?
AMD: AMD Ryzen 7000 CPUs have the same basic graphics engine with 2 AMD RDNA 2 CU's. The built-in graphics is meant to provide basic display-out capabilities for troubleshooting, as well as enough performance for watching videos and doing basic office tasks. The built-in graphics resides on the I/O die and is a self-contained unit with its own L2 cache. It does not access the L3 cache on any of the compute dies.
Can we expect BIOS-level scheduler toggles such as "prefer cache," and "prefer frequency" to be incorporated to Ryzen Master? Able to they apply on-the-fly without restart?
AMD: Currently, as you may know, the CCD/Thread optimizing for AMD 3D V-Cache is done via the OS and Microsoft's Xbox Game Bar, when gaming. We can see if there is a desire to be able to manually toggle the CCD, besides disabling one via Ryzen Master or in the BIOS.
TPU: Can you please detail the technical reason behind lowering the Tjmax value to 89 Celsius, down from 95C?
AMD: The AMD 3D V-Cache DIE requires certain power and voltage. 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. As a result you see our Ryzen 7000 Series processors with AMD 3D V-Cache have an official TDP of 120 W, instead of 170 W for some of the non-3D V-Cache versions. This is by design and also means we could run a lower TjMax.
With that reduced TDP we do see many of the 3rd party coolers that are confirmed to be compatible and working well with AMD Ryzen 7000 Series processors, to be work great on Ryzen 7000 processors with AMD 3D V-Cache.
TPU: What happens if I run a game in the foreground and a renderer in the background? What if I alt+tab and switch away from the game?
AMD: The AMD 3D V-Cache CCD is utilized for any 3D application that is running. Any other workloads are scheduled to be executed by the second CCD (should the CPU in question feature two CCDs). When performing a combination of these workloads, both CCDs will be utilized accordingly.
TPU: How does the PPM Driver detect a game? Just based on MS Game Bar detection?
AMD: Essentially when a Ryzen 7000X3D processor goes into "game mode", it's because Xbox game bar detects a game is running and puts the workload on the CCD with the AMD 3DV-cache technology.
TPU: The 7800X3D will run at optimum performance without any Performance Optimizer Driver / PPM Driver / Game Bar?
AMD: We always recommend to follow our teams instructions when testing AMD Processors. This includes installing the correct AMD Chipset Software as well as ensuring you are running on an optimized OS, for testing AMD 3D V-Cache technology. With a single CCD product with AMD 3D V-Cache technology you will find that a workload capable of benefiting from higher levels of L3 cache, will automatically see optimized performance, when the basic steps are followed.
TPU: In our testing, we noticed some outliers to the 3DV cache optimization. Is AMD identifying and optimizing for these games? Will we see AMD Chipset Software receive more frequent updates for game optimizations going forward?
AMD: While some games highly benefit from having more L3 cache, other may see less of a performance jump. Similar to when AMD first introduced Ryzen and Threadripper CPUs, with Chiplet design, and as we introduced the Ryzen 7 5800X3D processor, we are partnering closely with Microsoft to help optimize the built in thread scheduler in Windows for AMD Ryzen & Threadripper processors to ensure full benefit from our technologies. Additionally, we continue to work closely with Game Developers to ensure game threads are optimally scheduled to take advantage of the large AMD 3D V-Cache technology available on Ryzen 7000X3D processors.
Catch the TechPowerUp Reviews of the Ryzen 9 7950X3D | Ryzen 7 7800X3D | Ryzen 9 7950X3D with non-X3D CCD Disabled
29 Comments on Ryzen 7000X3D Series: A Brief Technical Chat with AMD
YOLO?
Additionally, over here DDR5 is still 2x the price of DDR4, as well. I'm waiting it out...
As I said many times, before it was never thermally limited.
I just got my 7800x3d last week.
Here's the deal: I game & work at 4k whenever possible, and I am running an RX-6900XT which has turned out to be a very nice card which has exceeded my expectations for it, and am not unhappy with it even considering that if I had waited another 4-5 months I could have saved $200-$300...but, I had decided I'd waited long enough and made the purchase, anyway! This is not a complaint, btw...;) (We can always save money by waiting, of course, so I don't regret the purchase at all.)
OK, I had thought about simply sticking with the x570 and going with the 5800X3D, as the most cost-effective move I could make, and it would be. But--the AM4 socket run is done, with the 5800X3D apparently being the icing on the cake for a super compatible AM4 conclusion.
OTOH, AM5 is just beginning its multi-year run, which promises to be a doozy, indeed. Too early to tell, of course, but Zen 5 is apparently shaping up to be a real barn-burner, an Intel derrière' spanker of great renown, so if I'm going to go to AM5 anyway, and I am, I see little point in delaying the transition by putting yet more $$$ into AM4.
However, I could wait....of course...like always, and with patience comes a savings in $$$ and a likely performance uptick in the AM5 new-peripherals/components costs.
Right now, I'm leaning towards keeping the 3900X for a bit longer, and going with an AM5 7950X3D in the 2H of this year. But things are still fluid. What do some of you guys think? Maybe a couple of you came off a 3900X and jumped into a AM5 X3D CPU, yourselves. If you did, what are your observations, so far?
The reason I really do want to keep things in limbo until sometime in the 2H of this year is because I want to give the motherboard bios creators more time to shore up and debug their bios files for AM5, including the usual AMD AGESA's of course, as well as each motherboard maker's custom bios code for its own motherboard hardware, etc. All comments welcome!
I can tell you that a 7800X3D struggles if you have multiple displays and you plan on playing a game on one and do other things on the other displays at the same time. Something that isn't an issue on a regular 7700X. I assume this has something to do with the cache.
At the end of the day, if you are happy with the performance you're getting out of your system right now, I see no reason to upgrade. Do so when a game you want to play doesnt perform the way you want it to perform given the resolution and visual fidelity you like to set.
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.
[INDENT]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.[/INDENT]
The fook are these canned responses? Next time please interview the engineer, not marketing.
Thanks for the article thou.
It takes 3-4 sentences to answer that simple question :slap: