NVIDIA B300 SXM6 AC vs NVIDIA RTX A400 Comparison

The Verdict

The NVIDIA B300 SXM6 AC and NVIDIA RTX A400 occupy entirely separate corners of the GPU landscape. The B300 SXM6 AC is a server-scale compute accelerator built for massive parallel workloads, while the RTX A400 is a low-profile workstation card designed for basic graphics and display tasks. The recorded data shows a single head-to-head benchmark, Geekbench OpenCL, where the B300 SXM6 AC scores 369,831 against the RTX A400's 22,844, a delta of 1518.9%. The B300 SXM6 AC wins the only shared test, giving it a 1-0 record in the head-to-head comparison.

The B300 SXM6 AC sits at the 100th percentile of all GPUs in the database, meaning it outperforms every other recorded GPU. Its nearest rivals include the NVIDIA B200, which scores 345,482 (7% behind), the NVIDIA H200 NVL at 334,891 (10.4% behind), the AMD Instinct MI300X at 317,994 (16.3% behind), and the NVIDIA L40S at 295,763 (25% behind). The RTX A400, by contrast, sits at the 35th percentile, with its nearest rivals being the NVIDIA GeForce MX230 (0% delta), NVIDIA Quadro P2000 (0.5% ahead), Intel Iris Pro Graphics 6200 (0.6% behind), and AMD Radeon 760M (1% behind). The data indicates the B300 SXM6 AC is for organizations running AI training, scientific simulation, or large-scale inference, while the RTX A400 serves basic workstation duties where a small, low-power GPU with display outputs is sufficient.

Architecture Differences

The B300 SXM6 AC uses the GB110 chip built on Blackwell Ultra architecture, fabricated on a 5 nm process at TSMC. It packs 208,000 million transistors across a 1628 mm² die, yielding a transistor density of 127.8M per mm². The RTX A400 uses the GA107 chip on Ampere architecture, built on an 8 nm process at Samsung, with 8,700 million transistors on a 200 mm² die, giving a density of 43.5M per mm². The B300 SXM6 AC represents a newer generation, classified as Server Blackwell (Bxx), while the RTX A400 belongs to Workstation Ampere (Ax000).

Memory configurations diverge sharply. The B300 SXM6 AC carries 288 GB of HBM3e on an 8192-bit bus, delivering 8.19 TB/s of bandwidth. The RTX A400 has 4 GB of GDDR6 on a 64-bit bus, providing 96.00 GB/s. The B300 SXM6 AC's memory clock is listed as 2000 MHz with 8 Gbps effective, while the RTX A400 runs at 1500 MHz with 12 Gbps effective. The B300 SXM6 AC has 18,944 shading units, 592 TMUs, 24 ROPs, and 592 tensor cores. The RTX A400 has 768 shading units, 24 TMUs, 16 ROPs, 6 RT cores, and 24 tensor cores. The B300 SXM6 AC does not list RT core counts in the database.

Compute throughput differs by orders of magnitude. The B300 SXM6 AC delivers 76.99 TFLOPS FP32 and 76.99 TFLOPS FP16 (1:1 ratio). The RTX A400 delivers 2.706 TFLOPS FP32 and 2.706 TFLOPS FP16 (1:1). Pixel rates are 48.77 GPixel/s for the B300 SXM6 AC versus 28.19 GPixel/s for the RTX A400. Texture rates are 1,202.9 GTexel/s against 42.29 GTexel/s.

Power and physical design differ completely. The B300 SXM6 AC has a TDP of 1100 W with a suggested PSU of 1500 W, comes as an SXM Module, and uses PCIe 6.0 x16. It has no display outputs. The RTX A400 has a TDP of 50 W, a suggested PSU of 250 W, is a single-slot card measuring 163 mm by 69 mm, uses PCIe 4.0 x8, has no power connectors, and provides 4x mini-DisplayPort 1.4a outputs. The B300 SXM6 AC lists no DirectX, OpenGL, or Vulkan API support, while the RTX A400 supports DirectX 12 Ultimate (12_2), OpenGL 4.6, and Vulkan 1.4.

The B300 SXM6 AC was released on 2025-09-10, with the RTX A400 released on 2024-04-15. The B300's predecessor is Server Hopper and its successor is Server Rubin. The RTX A400's predecessor is Quadro Turing and its successor is Workstation Ada. Both are listed as Active in production status.

Where Each One Wins

The B300 SXM6 AC wins decisively in raw compute. Its Geekbench OpenCL score of 369,831 is 1518.9% higher than the RTX A400's 22,844. The B300 SXM6 AC's average benchmark score of 369,831 places it at the 100th percentile of all GPUs. It leads its nearest rival, the NVIDIA B200, by 7%, the H200 NVL by 10.4%, the MI300X by 16.3%, and the L40S by 25%. This GPU is built for workloads where memory capacity and bandwidth are critical: 288 GB of HBM3e with 8.19 TB/s bandwidth enables large model training and inference tasks that would be impossible on smaller cards.

The RTX A400 wins in every category related to practical workstation use. It has display outputs (4x mini-DisplayPort 1.4a), supports modern graphics APIs (DirectX 12 Ultimate, OpenGL 4.6, Vulkan 1.4), fits in a single slot at 163 mm length, draws only 50 W with no power connectors, and requires a 250 W PSU. Its nearest rival comparisons show it is competitive within its class: it matches the GeForce MX230 (0% delta), sits 0.5% behind the Quadro P2000, 0.6% ahead of the Intel Iris Pro Graphics 6200, and 1% ahead of the AMD Radeon 760M. The RTX A400's benchmark portfolio includes PassMark DirectX 9 (87), DirectX 10 (32), DirectX 11 (37), DirectX 12 (27), G2D (899), G3D (5983), and GPU compute (2557), plus Geekbench Vulkan at 22,237. These scores reflect a card suitable for basic 3D rendering, multi-monitor setups, and light compute tasks.

The B300 SXM6 AC has no display outputs and no graphics API support, making it unsuitable for direct video output. The RTX A400 cannot approach the B300's compute capacity, making it unsuitable for large-scale AI or HPC work. The data shows a clean split: the B300 SXM6 AC dominates server compute, and the RTX A400 handles desktop workstation graphics.

FAQ

Q: How much faster is the NVIDIA B300 SXM6 AC than the NVIDIA RTX A400?

A: In the Geekbench OpenCL benchmark, the B300 SXM6 AC scores 369,831 versus 22,844 for the RTX A400, a delta of 1518.9%.

Q: What is the memory capacity difference between these two GPUs?

A: The B300 SXM6 AC has 288 GB of HBM3e memory on an 8192-bit bus with 8.19 TB/s bandwidth. The RTX A400 has 4 GB of GDDR6 on a 64-bit bus with 96.00 GB/s bandwidth.

Q: Which GPU supports display outputs?

A: Only the RTX A400 has display outputs, offering 4x mini-DisplayPort 1.4a. The B300 SXM6 AC has no outputs.

Q: What are the power requirements for each card?

A: The B300 SXM6 AC has a 1100 W TDP and a suggested PSU of 1500 W. The RTX A400 has a 50 W TDP, a suggested PSU of 250 W, and requires no power connectors.

Q: How does the B300 SXM6 AC compare to its nearest rivals?

A: It leads the NVIDIA B200 by 7% (345,482 score), the NVIDIA H200 NVL by 10.4% (334,891), the AMD Instinct MI300X by 16.3% (317,994), and the NVIDIA L40S by 25% (295,763).

Q: How does the RTX A400 compare to its nearest rivals?

A: It matches the NVIDIA GeForce MX230 (0% delta, 6077 score), trails the NVIDIA Quadro P2000 by 0.5% (6049), leads the Intel Iris Pro Graphics 6200 by 0.6% (6117), and leads the AMD Radeon 760M by 1% (6019).

Head-to-Head Benchmarks

The database records one head-to-head benchmark between these two GPUs: Geekbench OpenCL. The B300 SXM6 AC scores 369,831, while the RTX A400 scores 22,844. This gives the B300 SXM6 AC a 1518.9% advantage, representing the largest recorded margin in the comparison.

For the B300 SXM6 AC, this OpenCL result is its only benchmark entry, and it also serves as its average benchmark score. The 100th percentile ranking confirms that no GPU in the database records a higher score. The nearest rival data reinforces this dominance: the B200 trails by 7%, the H200 NVL by 10.4%, the MI300X by 16.3%, and the L40S by 25%. These gaps are substantial, but they are measured in single-digit or low-double-digit percentages compared to the B300's 1518.9% lead over the RTX A400.

The RTX A400's benchmark results paint a different picture. Its average benchmark score of 6,078 is derived from multiple tests: Geekbench OpenCL at 22,844, Geekbench Vulkan at 22,237, PassMark DirectX 9 at 87, DirectX 10 at 32, DirectX 11 at 37, DirectX 12 at 27, G2D at 899, G3D at 5,983, and GPU compute at 2,557. The 35th percentile placement indicates it outperforms roughly a third of all GPUs in the database. Its nearest rivals are clustered within 1% of its average score, showing that it sits in a tightly contested performance tier.

The single head-to-head result is decisive. The B300 SXM6 AC delivers compute performance that is more than sixteen times higher than the RTX A400 in the only test both cards share. The architecture gap explains this: the B300 uses a 5 nm Blackwell Ultra design with 208,000 million transistors and 18,944 shading units, while the RTX A400 uses an 8 nm Ampere chip with 8,700 million transistors and 768 shading units. The B300's FP32 throughput of 76.99 TFLOPS is roughly 28 times the RTX A400's 2.706 TFLOPS, and its texture rate of 1,202.9 GTexel/s is roughly 28 times the A400's 42.29 GTexel/s. The B300's memory bandwidth of 8.19 TB/s is over 85 times the A400's 96.00 GB/s.

The RTX A400 does have advantages in the recorded data, but they are not compute-related. It supports DirectX 12 Ultimate, OpenGL 4.6, and Vulkan 1.4, while the B300 lists no API support. It provides 4x mini-DisplayPort 1.4a outputs, while the B300 has none. It operates at 50 W TDP versus 1100 W, requires no power connectors, and fits in a single slot at 163 mm. These factors make the RTX A400 functional for desktop graphics work, but the benchmark data shows no scenario where it approaches the B300's compute capability.

The wins tally stands at 1 for the B300 SXM6 AC and 0 for the RTX A400. The head-to-head comparison is limited to a single test, but that test covers general-purpose GPU compute, which is the primary use case for the B300. The RTX A400's PassMark results, which include DirectX and 2D tests, are not shared with the B300, so no direct comparison exists for graphics-specific workloads. The database records what it records: one test, one winner, a 1518.9% margin, and two GPUs that serve fundamentally different purposes.