What is AMD 3D V-Cache? Here’s how it could change PC gamingJanuary 12, 2022
AMD announced the Ryzen 7 5800X3D at CES 2022, bringing the world’s first processor with 3D V-Cache to market. It’s an interesting CPU, outclassing the more expensive flagships from AMD and Intel. To understand why, you need to get up to speed on what AMD 3D V-Cache is, the performance it could offer, and why it’s important.
3D V-Cache is just a different way to lay out a processor, one that leaves more room for cache on the chip. It could be a major shift for AMD, and it could have an impact on many generations to come. We’re going to break down if it’s really the revolution AMD has pitched it as, or if it’s just marketing hot air.
What is AMD 3D V-Cache?
AMD 3D V-Cache is a packaging technology that stacks additional layers of cache on top of a CPU. It sounds complex, and from an engineering perspective, it is, but it’s not hard to understand what AMD’s tech is doing. Instead of laying the cache next to the processor as has been traditionally done, AMD is stacking the cache on top to squeeze more on the chip.
It’s a different way to lay out a processor, and thanks to advancements in how CPU makers put components on a chip, AMD is able to squeeze on more cache without making a massive CPU. AMD has only framed the additional cache in the realm of gaming, where the company says it can offer a 15% improvement on average.
To understand why, it’s important to understand what the cache is doing. Your processor has three levels of cache, with the lowest being L3, or level 3, cache. Each cache level is smaller in size but faster in speed, acting as a memory chain to your processor that can serve up instructions as they’re needed.
Think about cache like a supply chain. Your RAM is like a national warehouse, the L3 cache is a regional distribution center, and so on through the L2 and L1 caches. For 3D V-Cache, we’re talking about additional L3 cache, the slowest level on your CPU. That’s only relatively slow, though — each cache layer is still significantly faster than your hard drive or RAM.
More L3 cache allows the processor to stream and store more instructions, decreasing the number of times it needs to pull instructions from RAM. Naturally, this doesn’t provide a performance benefit in all situations. However, in scenarios where the CPU is handling multiple instructions, such as gaming, an additional L3 cache should provide a big uplift.
Why not just more cache on the processor? AMD doesn’t want to place all of its eggs in one basket. Layering more cache on the CPU opens up the chance for defeats, rendering the entire CPU useless. 3D V-Cache sits separate from the CPU die, close to the processor but not part of it. That provides the bandwidth benefits brought by cache being close to the processor without the risk.
Right now, we only have one processor that comes with 3D V-Cache: The Ryzen 7 5800X3D. It comes with an additional 64MB of 3D V-Cache, but AMD says its packaging tech can scale up to 192MB. As 2022 begins, and we start looking toward AMD’s Ryzen 7000 CPUs, we’ll likely see a lot more 3D V-Cache.
3D V-Cache processors
3D V-Cache is a technology that should eventually make its way throughout AMD’s product stack. For now, we only have a single processor with it: The Ryzen 7 5800X3D. It’s due out in the spring, and it comes with the same eight cores and 16 threads as the Ryzen 7 5800X. The big difference is the 64MB of 3D V-Cache, bringing the total L3 cache to 96MB.
AMD will likely release more 3D V-Cache processors soon, but they won’t come from the Ryzen range. Since the launch of third-gen AMD Epyc server processors, the company has talked about a refresh to the range that includes 3D V-Cache. AMD says the 256MB of the flagship Epyc 7763 can go as high as 768MB.
Throughout 2022, we’ll likely see 3D V-Cache be a cornerstone of AMD’s processor announcements. The first Ryzen processor seems like a proof of concept — a functional chip that can serve as a reference point for future Ryzen and Epyc designs. Cache has much more impact in the data center, and AMD is likely certifying the tech before deploying it to a fleet of servers.
3D V-Cache performance
Performance data is sparse for 3D V-Cache right now. AMD has only announced a single processor sporting the packaging tech, and it hasn’t arrived yet. We’re going based off data provided by AMD, and we always suggest waiting for third-party testing to validate.
The Ryzen 7 5800X3D is an interesting processor based on what AMD has said. Instead of comparing it to the base Ryzen 7 5800X, AMD put it up against the Ryzen 9 5900X and Core i9-12900K. Ryzen 7 processors aren’t supposed to compete with Ryzen 9 and Core i9 chips, setting the tone for what 3D V-Cache can offer gamers.
For specifics, AMD says the Ryzen 7 5800X3D can offers around a 15% boost at 1080p compared to the Ryzen 9 5900X. In Watch Dogs Legion, AMD says the new chip offers a 36% boost, and in Far Cry 6, a 24% boost. Keep in mind that the Ryzen 7 5800X3D comes with four fewer cores than the Ryzen 9 5900X, illustrating how much 3D V-Cache can improve performance while gaming.
More impressive is that AMD says the Ryzen 7 5800X3D can match or exceed Intel’s Core i9-12900K. We rate Intel’s current flagship as the best processor for gaming, but if AMD’s numbers are accurate, the Ryzen 7 5800X3D could take that crown. In titles like Final Fantasy XIV, AMD says it’s seeing up to a 17% improvement over the Core i9.
Although AMD’s claims are impressive, it’s important to take them with a dose of reality. AMD only shared numbers for 1080p. As the resolution scales up, the processor plays less of a role in performance. It’ll be important to look out for 1440p and 4K benchmarks once the processor launches to see how it actually stacks up to flagships.
A packaging revolution?
AMD is making a big deal out of 3D V-Cache, and for good reason. We need to wait to test the packaging tech before drawing conclusions, but AMD’s numbers are impressive, and CPU cache can have a huge impact on gaming. Although we don’t have third-party testing on 3D V-Cache, we already know how Ryzen prefers fast memory.
Without getting too deep in the weeds, Ryzen processors use chiplets instead of a single die. By parting out the components of the processor, AMD chips have a higher latency than their Intel counterparts. To counteract that, AMD includes a large amount of L3 cache and dense interconnects. And when it comes to RAM, faster speeds further improve the situation brought on by AMD’s chiplet architecture design.
3D V-Cache is taking what was meant to counteract a performance deficit and turning it into a performance advantage. More L3 cache doesn’t improve latency, but it allows more data to be stored in the CPU instead of the RAM. In turn, that reduces the total latency — the data coming from the RAM and flowing to the CPU — by allowing more of it to stay on the chip before being flushed out.
On a technical level, 3D V-Cache is more than marketing hype. That said, it will likely offer only a marginal improvement at higher resolutions. The real reason to get excited about 3D V-Cache is AMD’s future processor generations, where architectural improvements and 3D V-Cache together could bring large leaps in performance.
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