GPU Comparison

AMD Instinct MI300X and NVIDIA L40 are both high-end accelerators, but they target different corners of the compute market. The data shows a single head-to-head benchmark result, with the NVIDIA L40 taking a narrow win in Geekbench OpenCL, yet the broader benchmark averages and architectural profiles reveal two very distinct tools for different jobs.

Head-to-Head Benchmarks

The only direct benchmark comparison available is Geekbench OpenCL, where the NVIDIA L40 scores 330,926 against the AMD Instinct MI300X’s 317,994. That is a delta of -3.9% for the AMD part, meaning the L40 leads by roughly 4% in this specific test. It is a modest margin, not a decisive victory, and it reflects a single workload rather than a comprehensive suite.

Looking at the average benchmark scores tells a slightly different story. The MI300X has an average score of 317,994, which is identical to its single OpenCL result since that is its only recorded benchmark. The L40, however, has two benchmarks: its OpenCL score of 330,926 and a Vulkan score of 237,295, which pulls its average down to 284,111. That places the MI300X 10.7% ahead of the L40 in average score, a reversal of the single-test result.

The nearest-rival data adds context. The MI300X sits 7.5% above the NVIDIA L40S and 10.7% above the NVIDIA RTX 6000 Ada Generation, while trailing the NVIDIA H200 NVL by 5% and the NVIDIA B200 by 8%. The L40, by contrast, is 13.1% ahead of the NVIDIA L20 but 1.1% behind the RTX 6000 Ada and 3.9% behind the L40S. So while the L40 wins the direct OpenCL clash, the MI300X’s average score is higher than the L40’s average, and it competes in a higher performance tier overall.

The deltaPct values are asymmetric between the two cards. From the MI300X’s perspective, the L40 is not listed among its nearest rivals; the closest NVIDIA parts are the H200 NVL, L40S, B200, and RTX 6000 Ada. From the L40’s perspective, the MI300X is its fourth nearest rival with a -10.7% delta, meaning the MI300X’s average score is 10.7% higher. This suggests that in aggregate compute performance, the MI300X outclasses the L40, even though the L40 takes the single OpenCL benchmark.

Where Each One Wins

The NVIDIA L40 wins the only direct benchmark, Geekbench OpenCL, with a 3.9% edge over the MI300X. That is a real, measurable win in a general compute workload. The L40 also brings a Vulkan score of 237,295, which the MI300X cannot match because it has no Vulkan support at all. For any application that relies on Vulkan rendering or compute, the L40 is the only option here.

The AMD Instinct MI300X wins on raw average benchmark score, posting 317,994 against the L40’s 284,111. That is a 10.7% advantage, driven by the MI300X’s single high OpenCL result versus the L40’s lower Vulkan score dragging its average down. The MI300X also has a higher percentile ranking: it sits at the 100th percentile of all GPUs, while the L40 sits at the 99th. That one-percentile gap reflects the MI300X’s position at the very top of the performance distribution.

Architecturally, the wins are clear-cut. The MI300X is built for massive memory and bandwidth: 192 GB of HBM3 on an 8192-bit bus delivering 5.32 TB/s. The L40 has 48 GB of GDDR6 on a 384-bit bus at 864.0 GB/s. That is a 4x difference in capacity and a 6x difference in bandwidth, which matters enormously for large model inference or dataset processing. The L40 counters with display outputs (4x DisplayPort 1.4a) and full graphics API support (DirectX 12 Ultimate, OpenGL 4.6, Vulkan 1.4), while the MI300X has no display outputs and no graphics APIs. The L40 is a compute-plus-visualization card; the MI300X is pure compute.

The Verdict

Choose the NVIDIA L40 if your workload is graphics-adjacent or requires Vulkan. Its Vulkan score of 237,295 is a capability the MI300X simply does not have, and its OpenCL win over the MI300X shows it is no slouch in general compute either. The L40 also fits in a dual-slot PCIe 4.0 x16 form factor with a 300 W TDP and a 1x 16-pin power connector, making it far easier to integrate into a standard server or workstation. Its 48 GB of GDDR6 is ample for many rendering, simulation, or mid-sized inference tasks.

Choose the AMD Instinct MI300X if your priority is maximum memory capacity and bandwidth. The 192 GB of HBM3 at 5.32 TB/s is a generational leap over the L40’s 48 GB at 864.0 GB/s, and the 10.7% higher average benchmark score confirms its edge in raw compute. The MI300X is an OAM module with no display outputs and no graphics APIs, so it is strictly for headless compute clusters. Its 750 W TDP and 1150 W suggested PSU also demand serious power infrastructure.

The data does not support a single “better” card. The L40 wins the only direct test, but the MI300X wins the average and dominates memory capacity. For a builder with mixed compute and visualization needs, the L40 is the practical pick. For a dedicated AI or HPC node with massive memory requirements, the MI300X is the clear choice. There is no overlap in their strengths, so the decision comes down to workload, not performance hierarchy.

FAQ

Q: Which GPU has the higher average benchmark score?

A: The AMD Instinct MI300X has an average benchmark score of 317,994, which is 10.7% higher than the NVIDIA L40’s average of 284,111.

Q: Did the NVIDIA L40 win any direct benchmark against the MI300X?

A: Yes, in the Geekbench OpenCL test, the L40 scored 330,926 versus the MI300X’s 317,994, a 3.9% margin in favor of the L40.

Q: Can the AMD Instinct MI300X run Vulkan workloads?

A: No, the MI300X has no Vulkan support, while the NVIDIA L40 scores 237,295 in Geekbench Vulkan.

Q: How much memory does each card have?

A: The MI300X has 192 GB of HBM3, while the L40 has 48 GB of GDDR6.

Q: Which card has a higher memory bandwidth?

A: The MI300X offers 5.32 TB/s of bandwidth, compared to the L40’s 864.0 GB/s.

Q: What is the form factor difference?

A: The MI300X is an OAM module with no display outputs, while the L40 is a dual-slot PCIe card with 4x DisplayPort 1.4a outputs.

Architecture Differences

The two cards are built on fundamentally different architectures. The MI300X uses AMD’s CDNA 3.0 architecture on a chip called Aqua Vanjaram, fabricated on a 5 nm process at TSMC. It packs 153,000 million transistors on a 1017 mm² die, giving a transistor density of 150.4M per mm². The L40 uses NVIDIA’s Ada Lovelace architecture on the AD102 chip, also on a 5 nm TSMC process, but with 76,300 million transistors on a 609 mm² die, resulting in a lower density of 125.3M per mm².

The compute resources differ sharply. The MI300X has 19,456 shading units and 1,216 TMUs, but no ROPs, no ray tracing cores, and no tensor cores listed. Its pixel rate is 0 MPixel/s, and its texture rate is 2,553.6 GTexel/s. The L40 has 18,176 shading units, 568 TMUs, and 192 ROPs, plus 142 ray tracing cores and 568 tensor cores. Its pixel rate is 478.1 GPixel/s, and its texture rate is 1,414.3 GTexel/s.

The MI300X’s FP32 and FP16 performance are both listed at 81.72 TFLOPS with a 1:1 ratio. The L40’s FP32 and FP16 are both 90.52 TFLOPS, also 1:1. So the L40 has a higher raw floating-point throughput on paper, even though the MI300X wins on average benchmark score. The MI300X has no graphics API support (DirectX, OpenGL, Vulkan are all N/A), while the L40 supports DirectX 12 Ultimate (12_2), OpenGL 4.6, and Vulkan 1.4.

Specification Differences

The most glaring difference is memory. The MI300X offers 192 GB of HBM3 with an 8192-bit bus and 5.32 TB/s bandwidth. The L40 has 48 GB of GDDR6 with a 384-bit bus and 864.0 GB/s bandwidth. The MI300X’s memory clock is 1300 MHz (5.2 Gbps effective), while the L40 runs at 2250 MHz (18 Gbps effective).

Clock speeds also differ. The MI300X has a base clock of 1000 MHz and a boost clock of 2100 MHz. The L40 has a lower base of 735 MHz but a higher boost of 2490 MHz. This reflects the L40’s higher peak FP32 throughput of 90.52 TFLOPS versus the MI300X’s 81.72 TFLOPS.

Power and physical specs diverge significantly. The MI300X draws 750 W with no power connectors (OAM module) and a suggested PSU of 1150 W. The L40 draws 300 W with a 1x 16-pin connector and a 700 W suggested PSU. The MI300X is an OAM module with no dimensions given; the L40 is dual-slot, 267 mm long and 111 mm tall, with 4x DisplayPort 1.4a outputs.

Bus interfaces differ too: the MI300X uses PCIe 5.0 x16, while the L40 uses PCIe 4.0 x16. The MI300X has no display outputs, while the L40 has four. The MI300X’s production status is not listed, but the L40 is marked as end-of-life. Release dates are December 5, 2023, for the MI300X and October 12, 2022, for the L40. Neither card has a listed launch MSRP.