AMD Radeon RX 7900M vs NVIDIA L40S Comparison

The NVIDIA L40S and AMD Radeon RX 7900M occupy very different corners of the GPU landscape, one a dual-slot server accelerator built on Ada Lovelace, the other a mobile part from the Radeon RX 7000 series. Their recorded benchmark scores place them far apart, with the L40S averaging 295,763 across its tested workloads and the RX 7900M averaging 97,487. The L40S sits in the 99th percentile of all GPUs in the database, while the RX 7900M reaches the 94th percentile. These numbers alone suggest a wide gulf, but the details of architecture, memory, and feature sets reveal why each card exists and who should consider it.

FAQ

Q: How large is the performance gap between the NVIDIA L40S and the AMD Radeon RX 7900M?

A: The L40S leads in both shared benchmarks. In Geekbench OpenCL, it scores 330,727 versus 129,499, a 155.4% difference. In Geekbench Vulkan, it scores 260,799 versus 158,760, a 64.3% difference. The average benchmark score for the L40S is 295,763, while the RX 7900M averages 97,487.

Q: Which GPU has more memory and bandwidth?

A: The NVIDIA L40S ships with 48 GB of GDDR6 memory on a 384-bit bus, delivering 864.0 GB/s of bandwidth. The AMD Radeon RX 7900M has 16 GB of GDDR6 on a 256-bit bus, providing 576.0 GB/s.

Q: Are these GPUs from the same architectural generation?

A: No. The L40S uses NVIDIA's Ada Lovelace architecture on the AD102 chip, while the RX 7900M uses AMD's RDNA 3.0 architecture on the Navi 31 chip. Both are built on a 5 nm process at TSMC, but they diverge in nearly every other design choice.

Q: What is the power draw difference?

A: The L40S has a TDP of 300 W and requires a 16-pin power connector with a 700 W suggested PSU. The RX 7900M has a TDP of 180 W and uses no external power connectors, as it is an integrated mobile part.

Q: Which GPU has a higher transistor count?

A: The NVIDIA L40S packs 76,300 million transistors on a 609 mm² die, for a density of 125.3 million per mm². The AMD Radeon RX 7900M contains 57,700 million transistors on a 529 mm² die, with a density of 109.1 million per mm².

Q: How do their nearest rivals compare?

A: The L40S is 3% ahead of the NVIDIA RTX 6000 Ada Generation and 4.1% ahead of the NVIDIA L40, but 7% behind the AMD Instinct MI300X and 11.7% behind the NVIDIA H200 NVL. The RX 7900M is 0.4% ahead of the AMD Radeon Pro VII, 5.4% ahead of the AMD Radeon Instinct MI60, and 6.3% ahead of the NVIDIA RTX A4500, but 4.3% behind the NVIDIA Quadro RTX 6000.

Architecture Differences

The L40S and RX 7900M could not be more different in their design philosophies. The L40S is built on the AD102 chip, the largest Ada Lovelace die, with 76,300 million transistors spread across 609 mm². The RX 7900M uses Navi 31, a chiplet-based design from RDNA 3.0, with 57,700 million transistors on a 529 mm² die. Both use TSMC's 5 nm process, which explains their relatively high transistor densities, 125.3 million per mm² for NVIDIA and 109.1 million per mm² for AMD.

Compute resources tell a stark story. The L40S carries 18,176 shading units, 568 texture mapping units, and 192 ROPs. It also includes 142 RT cores and 568 tensor cores, the latter being crucial for AI workloads. The RX 7900M has 4,608 shading units, 288 TMUs, and 192 ROPs, with 72 RT cores and no tensor cores at all. The L40S has nearly four times the shading units and double the TMUs, though both share the same ROP count. This disparity in raw compute is reflected in their FP32 throughput: 91.61 TFLOPS for the L40S versus 38.52 TFLOPS for the RX 7900M. Interestingly, the RX 7900M achieves 77.05 TFLOPS in FP16 due to a 2:1 ratio, while the L40S matches its FP32 rate at 91.61 TFLOPS with a 1:1 ratio.

Memory architecture reinforces the divide. The L40S uses a 384-bit bus with 48 GB of GDDR6, reaching 864.0 GB/s. The RX 7900M uses a 256-bit bus with 16 GB of GDDR6, capping at 576.0 GB/s. Both run their memory at the same 2250 MHz, translating to 18 Gbps effective, but the wider bus on the L40S gives it a 50% bandwidth advantage. The L40S also has higher pixel and texture rates, 483.8 GPixel/s and 1,431.4 GTexel/s, versus 401.3 GPixel/s and 601.9 GTexel/s for the RX 7900M.

Clock speeds add another layer. The RX 7900M has a higher base clock at 1825 MHz and a boost of 2090 MHz, while the L40S starts at 1110 MHz and boosts to 2520 MHz. The L40S ultimately extracts more performance per clock from its massive compute array, but the RX 7900M's higher base frequency hints at a design tuned for efficiency within a mobile power envelope. The L40S draws 300 W and needs a 16-pin connector, while the RX 7900M is rated at 180 W with no external power connectors, reflecting its IGP form factor.

Feature support is nearly identical on paper. Both support DirectX 12 Ultimate (12_2), OpenGL 4.6, and Vulkan 1.4. Both use PCIe 4.0 x16. Display outputs differ: the L40S offers 1x HDMI 2.1 and 3x DisplayPort 1.4a, while the RX 7900M's outputs are listed as portable device dependent. The L40S is a dual-slot card measuring 267 mm in length, while the RX 7900M has no listed dimensions due to its mobile nature.

The Verdict

The data points to a clear split: the NVIDIA L40S is for compute-heavy server workloads, while the AMD Radeon RX 7900M is a mobile part that trades raw power for portability. In every shared benchmark, the L40S wins decisively. Its Geekbench OpenCL score is 155.4% higher, and its Vulkan score is 64.3% higher. The L40S also lands in the 99th percentile of all GPUs, compared to the 94th percentile for the RX 7900M.

The L40S is the obvious choice for anyone needing maximum FP32 throughput, 48 GB of memory, or tensor core acceleration. Its 91.61 TFLOPS in both FP32 and FP16 makes it a versatile accelerator for scientific computing, rendering, and AI inference. The RX 7900M, by contrast, is suited for mobile systems where 180 W is the ceiling. Its 38.52 TFLOPS of FP32 and 77.05 TFLOPS of FP16 are respectable for a laptop part, and its 16 GB of memory is adequate for many workloads, but it cannot match the L40S in sustained compute.

The nearest rival data reinforces this. The L40S competes with other server accelerators like the NVIDIA H200 NVL, which is 11.7% faster, and the AMD Instinct MI300X, which is 7% faster. The RX 7900M competes with older workstation cards like the NVIDIA Quadro RTX 6000 and AMD Radeon Pro VII, sitting just 0.4% above the latter. These are different leagues, and the benchmark database treats them as such.

Specification Differences

The two GPUs differ across nearly every specification field. The L40S uses the AD102 chip with Ada Lovelace architecture, while the RX 7900M uses Navi 31 with RDNA 3.0. Transistor counts are 76,300 million versus 57,700 million, and die sizes are 609 mm² versus 529 mm². Transistor density favors NVIDIA at 125.3 million per mm², compared to 109.1 million per mm².

Memory is a major differentiator. The L40S offers 48 GB of GDDR6 on a 384-bit bus with 864.0 GB/s bandwidth. The RX 7900M offers 16 GB on a 256-bit bus with 576.0 GB/s. Clock speeds also differ: the L40S has a base of 1110 MHz and boost of 2520 MHz, while the RX 7900M has a base of 1825 MHz and boost of 2090 MHz. Memory clocks are identical at 2250 MHz, but effective data rates are the same 18 Gbps.

Compute units diverge sharply. The L40S has 18,176 shading units, 568 TMUs, 192 ROPs, 142 RT cores, and 568 tensor cores. The RX 7900M has 4,608 shading units, 288 TMUs, 192 ROPs, and 72 RT cores, with no tensor cores. Pixel rates are 483.8 GPixel/s versus 401.3 GPixel/s, and texture rates are 1,431.4 GTexel/s versus 601.9 GTexel/s. FP32 output is 91.61 TFLOPS versus 38.52 TFLOPS, while FP16 is 91.61 TFLOPS versus 77.05 TFLOPS.

Power and physical specs differ as well. The L40S has a 300 W TDP, dual-slot form factor, a 16-pin power connector, and a 700 W suggested PSU. The RX 7900M has a 180 W TDP, IGP form factor, no power connectors, and no suggested PSU. The L40S measures 267 mm in length, while the RX 7900M has no recorded dimensions. Release dates are also apart: the L40S launched on October 12, 2022, and is end-of-life, while the RX 7900M launched on October 18, 2023, and remains active.

Head-to-Head Benchmarks

The database includes two direct comparisons between these GPUs, both in Geekbench workloads. The first is Geekbench OpenCL, where the L40S scores 330,727 against 129,499 for the RX 7900M. That is a 155.4% advantage, the largest margin in any shared test. The second is Geekbench Vulkan, where the L40S scores 260,799 against 158,760, a 64.3% lead.

These results align with the architectural differences. OpenCL tends to stress raw compute throughput, and the L40S's 18,176 shading units and 91.61 TFLOPS of FP32 dwarf the RX 7900M's 4,608 units and 38.52 TFLOPS. Vulkan is more balanced, but the L40S still wins by nearly two-thirds. The L40S also benefits from higher boost clocks, 2520 MHz versus 2090 MHz, and a wider memory bus that delivers 864.0 GB/s.

The average benchmark score tells a similar story. The L40S averages 295,763, while the RX 7900M averages 97,487. The L40S's nearest rivals, the NVIDIA RTX 6000 Ada Generation at 287,237 and the NVIDIA L40 at 284,111, sit just below it, while the AMD Instinct MI300X at 317,994 and NVIDIA H200 NVL at 334,891 sit above. The RX 7900M's rivals are far lower, with the AMD Radeon Pro VII at 97,131 and the NVIDIA Quadro RTX 6000 at 101,872. This places the RX 7900M in a performance tier roughly one-third that of the L40S.

Where Each One Wins

The NVIDIA L40S wins every benchmark it shares with the RX 7900M, but its strengths extend beyond raw scores. Its 48 GB of memory and 864.0 GB/s bandwidth make it suitable for large datasets, while its tensor cores provide hardware acceleration for AI workloads. The 1:1 FP16 ratio means it can sustain high throughput across precision formats, a feature the RX 7900M cannot match due to its 2:1 ratio. The L40S also benefits from a higher percentile ranking, 99th versus 94th, indicating it sits near the top of the entire GPU database.

The AMD Radeon RX 7900M wins in efficiency and portability. Its 180 W TDP is 120 W lower than the L40S, and its IGP form factor means it can be integrated into mobile devices without external power connectors. It also has a higher base clock, 1825 MHz versus 1110 MHz, which could translate to better responsiveness in lightly threaded tasks, though the database does not include tests for such scenarios. Its 2:1 FP16 ratio gives it a respectable 77.05 TFLOPS in half precision, which narrows the gap to the L40S in that specific metric.

For use cases, the choice is clear. The L40S is for server racks, rendering farms, and AI inference nodes where power draw is secondary to throughput. The RX 7900M is for high-end laptops and mobile workstations where the 180 W envelope and lack of external power connectors are non-negotiable. The benchmark data shows no scenario where the RX 7900M overtakes the L40S in compute performance, but the mobile part's existence is justified by its form factor and efficiency, not by raw score comparisons.