What is 3D V-Cache? – Dot Esports
AMD announced its first CPU using 3D V-Cache with the Ryzen 7 5800X3D this spring. While its presentation explains some of the benefits of the new design architecture, AMD doesn’t detail what makes 3D V-Cache so unique.
Here’s what you need to know about what 3D V-Cache is, how it works, and how gaming can benefit.
How CPU uses cache
To understand the potential benefits of 3D V-Cache, one must first understand how the processor uses cache. Cache is like a fallback for memory transfers, allowing processor cores to access RAM faster than pulling from main memory. Think of it as the difference between someone reaching for a water bottle right next to them and getting it from across the room.
Cache caches have different sizes and speeds, where L1 cache is the smallest and fastest cache and L3 cache is the slowest and largest cache. There is an L4 Cache, but it is not usually common in today’s chip architectures. Each cache is allocated to another cache until it reaches the processor. The caches go in order from L4 to L3 to L2 to L1 to the processor, according to Tech Society.
L3 and L2 caching, although slower, boosts processor performance by acting as a backup. Going back to the water analogy, think of each cache as a person holding water bottles. The person requesting water can get it from the water container closest to them, while the other two provide the person with their reserves when they run out. If the person farthest away has a large stock of water bottles, the system works faster due to excess supply and is efficient.
3D vs 2D
Until recent years, the processors on the market could only arrange these caches horizontally, with smaller silicon node dies allowing more space for the cache chiplets. New 3D printing technology now allows stacking of buffers vertically. 3D stacked cache chiplets increase the available storage per stack. Using the water bottle example, it’s like the person farthest away has two instances of water instead of just one.
2D cache is limited by how much capacity the chip can provide, with many chips offering L3 caches averaging 64MB or less. But using 3D stacked caching pushes that total much higher. AMD uses this technique to make 192MB of total L3 storage possible with speeds up to 2TB/s in the near term. 5800X3D. It achieves this by stacking two layers of 48MB L3 cache together in two chiplets.
While 192MB is an amazing leap from previous limits, the technology has much more potential. 3D stacking isn’t just limited to caching. Taiwan Semiconductor Manufacturing Company (TSMC) has proven that they can stack up to 12 layers of silicone on a chip. In essence, anything from the number of cores in the CPU to the GPU performance cores can be stacked in 3D.
How beneficial will gaming be?
Gamers with 3D stacking chips will benefit from the technique’s increased bandwidth. AMD says its 5800X3D chip offers a 15% performance boost over the Ryzen 9 5900 – a chip with more threads and cores. If AMD’s claims are correct, their 3D V-Cache chips provide half or even the full increase in generational performance without any other architectural changes. Intel also has stacking chips, but it uses a different technique for stacking.
With 3D V-Cache closer to consumers, expect this technology to expand in the coming years. AMD already has plans to introduce more 3D stacking chips in its “high-end” products, expanding the possibilities of how far gaming performance can go.
https://dotesports.com/hardware/news/what-is-3d-v-cache What is 3D V-Cache? – Dot Esports