What Nvidia’s Blackwell GPUs and PCIe 6/7 Mean for AI and Data Centers

At GTC 2024 Nvidia unveiled three Blackwell‑based server platforms: GB200, HGX B200 and HGX B100. GB200 combines two Blackwell GPUs with a Grace CPU, supporting internal NVLink v5 and PCIe 6.0, while the other models use a single Blackwell GPU each.

The new Quantum‑X800 InfiniBand platform, designed for Blackwell, offers 1.6 T optical modules. The Q3400‑RA 4U switch provides 72 OSFP ports, delivering 144 × 800 Gb/s links. ConnectX‑8 smart NICs are upgraded to XDR 800 Gb/s, backward‑compatible with NDR 400 Gb/s and HDR 200 Gb/s, and can use four 224 Gb/s 800 Gb/s optical modules.

As of 30 June 2024, Nvidia’s datasheets show Blackwell servers still ship with PCIe 5.0 NICs. For example, the DGX SuperPOD NVL72 uses 72 × 400 Gb/s ConnectX‑7 NICs with NDR 400 Gb/s optics, while the DGX B200 uses eight ConnectX‑7 NICs with four × 800 Gb/s NDR optics (2 × 400 Gb/s).

PCIe 6.0 doubles the bandwidth of the previous Hopper generation, moving to 64 GT/s per lane with PAM4 signaling and forward‑error correction. The standard is slated for commercial availability in 2024, with full compliance testing expected in 2025. PCIe 7.0, announced in early 2024, targets 128 GT/s and retains PAM4 and Flit encoding while doubling the physical layer frequency.

Industry players are already demonstrating PCIe 6.0 and 7.0 prototypes: Synopsys showed the first PCIe 6.0 IP interoperable with Intel test chips; Alphawave and Keysight achieved 64 GT/s with a PCIe 6.0 controller; Cadence and Rambus presented PCIe 7.0 IP suites, including controllers, retimers and switches; and Alphawave highlighted PAM4 SerDes solutions for next‑generation PCIe.

Market forecasts from Technavio predict the PCIe market will grow at a 28.22 % CAGR from 2023 to 2028, reaching $53.74 billion, and surpass $123.3 billion by 2033, with North America accounting for roughly 40 % of growth.

Given the imminent availability of 1.6 T optical modules in 2024, the article recommends monitoring vendors that serve AI‑driven demand, such as Zhongji Xuchuang, Tianfu Communication, and XinYisheng, as well as tracking the broader PCIe 6.0 supply chain and the new optical‑communication opportunities introduced by PCIe 7.0.