AMD Navi 31 with PCIe Gen5
AMD may become the first company to unveil its PCI-Express 5.0 graphics cards.
According to the GFX11 architecture patches that were recently discovered by Kepler_L2, AMD Navi 31 GPU should enable new standard for the upcoming Radeon RX 7000 series.
AMD Navi 31 GPU is part of the new RDNA3 GPU family, which is referred to as GFX11 by AMD in Linux kernel patches. Over the last week, AMD has deployed a significant number of updates for the new architecture, which are only the start of the new architecture enablement.
Kepler has been digging into those patches and discovering interesting tidbits that may later give AMD an advantage over competitors. One of such is PCIe Gen5 support, which has not yet been confirmed for GeForce RTX 40 series. It would be very strange, though, if NVIDIA did not support the new standard, as even the data-center H100 GPU already supports it.
PCIe Gen5 16x for Navi31 pic.twitter.com/f53270NXpE
— Kepler (@Kepler_L2) May 4, 2022
Just recently, AMD confirmed that Ryzen 7000 “Raphael” CPUs with Zen4 microarchitecture will support PCIe Gen5. Thus far, the company had only confirmed Gen5 support for its AM5 platform. This announcement means that in late 2022, AMD will have motherboards, CPUs and GPUs, all PCIe Gen5 capable.
AMD AM5 and Ryzen 7000 series with PCIe Gen5 support, Source: AMD
PCIe Gen5 has twice the bandwidth of PCIe Gen4, offering up to 32 Gigatransfers per second or 128 GB/s. This will have a significant impact on bandwidth for the next-gen storage, but should also unlock new possibilities for GPUs. In memory-intensive scenarios, GPU manufacturers always sought more capable interface solutions, such as SXM or NVLink, just to overcome the limitations of PCIe architecture.
PCI Express Standard, Source: PCI-SIG
The PCIe Gen5 patches were discovered for SOC21 (Navi 31) GPU thus far, but it is more than likely that all Navi 3X GPUs will launch with new interface. The question that remains is whether AMD intends to limit the number of lanes on low-end SKUs, which as proven with Radeon RX 6500XT and PCIe Gen4 x4 interface may have a significant impact on performance once used on older Gen3-capable platform.
| Rumored Specs of AMD RDNA3 GPUs | |||
|---|---|---|---|
| VideoCardz.com | |||
| Fabrication Node | TSMC 5nm + 6nm | TSMC 5nm + 6nm | TSMC 6nm |
| Architecture | AMD RDNA3 | AMD RDNA3 | AMD RDNA3 |
| GPU Package | Multi-Chip-Module (MCM) | Multi-Chip-Module (MCM) | Monolithic |
| Estimated GPU Size | ~800 mm² (or more) | TBC | ~440 mm² |
| Graphics Dies | 2 | 2 | 1 |
| Shader Engines | 6 | 4 | 2 |
| Shader Arrays | 12 | 8 | 4 |
| RDNA Workgroups (WGP) | 48 | 32 | 16 |
| Compute Units | 96 | 64 | 32 |
| Stream Processors | 12288 | 8192 | 4096 |
| GPU Clock | ~3.0 GHz | TBC | TBC |
| Memory & Bus | GDDR6 256-bit | GDDR6 192-bit | GDDR6 128-bit |
| Infinity Cache | 256 – 512MB | 256 – 384MB | 128 – 256MB |
| PCIe Interface | PCIe Gen5 | PCIe Gen5 | PCIe Gen5 |
| Release | Q3/Q4 2022 | Q3/Q4 2022 | Q1 2023 |
| Rumored SKU | Radeon RX 7900XT | Radeon RX 7700XT | Radeon RX 7600XT |
| FP32 Performance | 73 TFLOPS | TBC | TBC |
| All information is based on rumors | |||
Source: Kepler_L2
