3D V-Cache in high-end processors and mobile iGPUs?
AMD has launched the Ryzen 7 9800X3D with second-generation 3D V-Cache technology with a large cache in an extra chipset, which makes it a good (currently the best) CPU for gaming. But this technology is now likely to be deployed more widely. It’s apparently coming to high-performance Threadripper processors for the first time, and could even appear in APUs, i.e. mobile processors for laptops, perhaps as Infinity Cache for their GPUs.
AMD has not yet announced plans to release Ryzen Threadripper 9000 processors with the Zen 5 architecture, but they can be pretty much expected. These processors will be coming to the WRX90 platform boards (we assume TRX50 as well), and it seems that one sign of preparation has already appeared. In the UEFI of Asus WRX90 boards (it should be the Asus Pro WS WRX90E-Sage SE model), an item related to 3D V-Cache was found. However, no Threadrippers have this feature yet, so it will probably be a possibility with the new generation of Ryzen Threadripper (Pro) 9000 processors.
V-Cache on Threadrippers would be a novelty in itself, as already mentioned. Ad interestingly, it appears it will be used for more than just one CPU chiplet (which is how it is done in the Ryzen 9 7900X3D and 7950X3D, and probably future 9900X3D and 9950X3D as well). Those BIOSes from Asus have the ability to turn 3D V-Cache on and off, and not just globally. The option allows you to turn it on for one, two, or four “stacks” (with stack likely meaning one chiplet). So these 3D Threadrippers could have V-Cache under more, or even all, of their CPU core chiplets.
V-Cache will probably not be the standard and will only be present on some Threadripper models, you will also have to pay a little extra for it. Generally, the Threadripper platform (and WRX90 in particular) is never a cheap affair on its own either.
Not just Threadripper, APUs too?
Shortly after this hint surfaced, information that future Threadrippers will feature 3D V-Cache also appeared from the Chinese leakernicknamed zhangzhonghao on the Chiphell forum. According to them, sources from AMD partners or companies working on related hardware confirmed the information about “X3D” Threadrippers.
According to zhangzhonghao, these processors will have 3D V-Cache used for all CPU chiplets in the processor, i.e. for all cores. We suppose that in the case of Threadripper, the usual issue that V-Cache reduces the max turbo boost doesn’t matter as much as on client CPUs, because these CPUs have always used lower maximum boost clocks compared to regular Ryzen SKUs – the lower boost due to V-Cache will basically be hidden by this generally more conservative clock speed.
What’s even more interesting is that according to the same source, 3D V-Cache is also coming to APUs, i.e. mobile processors with integrated GPUs, which are now monolithic. These could benefit from 3D V-Cache not so much to boost the CPU’s gaming performance, but to boost the performance of their integrated GPUs. Gaming performance of graphics cores in APUs has long been limited by memory bandwidth (pretty much ever since the time APUs have appeared on market), and one solution that could help break this age-old limitation would be Infinity Cache, as found in discrete GPUs.
However, that would mostly help just the top APU models, while making the chips more expensive to produce for all models. But if Infinity Cache were implemented by adding an “X3D” chiplet to select SKUs only, it could finally be a viable solution, though it still wouldn’t be cheap, and thus would probably only apply to “premium” laptops. But it could be the kind of revolution in performance of integrated GPUs that has been longed for in vain until now.
According to zhangzhonghao, the technology won’t be used in desktop APUs, where the performance of the integrated graphics isn’t much of a pressing issue (since you can easily add a powerful discrete GPU to a PCIe ×16 slot). It will be used in laptops, especially high-end ones. However, it is not clear in which APU we can expect to see it for the first time.
AMD will release the Strix Halo in January (it should be labeled Ryzen AI Max 300), which will have 256-bit memory, a GPU with up to 2560 shaders (40 CUs), and up to 16 Zen 5 cores. The Zen 5 cores could come from the CPU chiplets used in the desktop and the entire processor is said to be assembled “2.5D” style in a TSMC InFO package. One can imagine that Strix Halo could be using 3D V-Cache for its CPU chiplets, but a V-Cache attached to the integrated GPU (which will be located in the IO chiplet) would be a big surprise. So it’s probably more reasonable to expect that the intitial mobile roll-out of 3D V-Cache won’t be in Strix Halo, and it will only come in some new next-gen APU coming further in the future, maybe something already based on Zen 6. In general, there is virtually no information about AMD’s post-Zen 5 processors yet.
Read more: APU Strix Halo partly revealed. AMD’s M3 Ultra has a TDP of up to 120 W
It should be added that in terms of CPU, there is already a gaming processor with 3D V-Cache for laptops on the market, the Ryzen 9 7945HX3D. This is essentially a laptop variant of the desktop Ryzen 9 7950X3D, and there will likely be a similar product released in the Ryzen 9000 generation. Such processors derived from the desktop Zen 5 design are codenamed Fire Range and should be revealed at CES 2025 in January.
Read more: 3D V-Cache for laptops: the Ryzen HX3D might be ideal for gamers
English translation and edit by Jozef Dudáš
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