AMD Radeon RX 6650M XT vs NVIDIA L4 Comparison

The NVIDIA L4 and AMD Radeon RX 6650M XT occupy very different corners of the GPU market, and the recorded data makes the split unmistakable. One is a single-slot server accelerator built on Ada Lovelace; the other is an end-of-life RDNA 2 mobile part. The head-to-head benchmark data shows the L4 with a commanding lead, roughly 83% ahead in the one shared test, but the underlying specifications reveal a more nuanced picture of where each design makes sense.

Head-to-Head Benchmarks

The database contains a single overlapping benchmark between these two, and it is decisive. In Geekbench OpenCL, the NVIDIA L4 scores 140838 against 76904 for the Radeon RX 6650M XT, an 83.1% advantage for the L4. That is not a close contest; it is a full performance class of separation.

Context from each card's rival set reinforces the gap. The L4 sits in the 95th percentile of all GPUs in the database, with its average benchmark score of 131072 landing within a fraction of a percent of the GeForce RTX 3090 Ti (131938 average, the L4 just 0.7% behind) and roughly 3% behind cards like the RTX 4000 Ada Generation, the A10M, and the Radeon PRO W6800. In other words, the L4 trades blows with full-size flagship-class hardware despite its compact single-slot form factor.

The RX 6650M XT sits in the 91st percentile with an average score of 76904. Its nearest rivals include the Radeon RX 6850M XT (78940 average, the 6650M XT 2.6% behind) and the Tesla P100 PCIe variants in both 12 GB and 16 GB forms (79396 and 79605 averages respectively, putting the AMD part 3.1% and 3.4% behind). That is respectable company for a mobile chip, but it is a tier below where the L4 operates.

The L4 also has a recorded Geekbench Vulkan score of 121306, a test for which the 6650M XT has no entry in the database, so no direct comparison can be drawn there. On the evidence available, the L4 wins the only head-to-head benchmark, one win to zero.

Where Each One Wins

The L4 wins on raw compute throughput, and by a wide margin. Its FP32 output of 30.29 TFLOPS is more than three times the 6650M XT's 9.896 TFLOPS. Texture fill rate tells the same story: 489.6 GTexel/s versus 309.2 GTexel/s. Memory capacity is another clear L4 advantage, 24 GB against 8 GB, paired with a wider 192-bit bus delivering 300.1 GB/s of bandwidth versus 256.0 GB/s on the narrower 128-bit interface. For workloads that need large models, big datasets, or sustained compute, the L4 is the only option of the two.

The 6650M XT fights back in a few specific categories. Pixel fill rate is nearly a tie, 154.6 GPixel/s against 163.2 GPixel/s for the L4, a gap of under 6% despite the L4's massive compute lead. Its clock speeds are far higher, with a 2416 MHz boost and a 2162 MHz game clock, compared to the L4's 2040 MHz boost from a 795 MHz base. Its memory also runs faster on a per-pin basis, at 16 Gbps effective versus 12.5 Gbps effective. And unlike the L4, it has display outputs, described as portable device dependent, which makes it the only one of the two that can actually drive a screen directly. The L4 has no outputs at all and is purely a compute device.

The FP16 comparison is worth noting: the L4 delivers 30.29 TFLOPS at a 1:1 ratio with FP32, while the 6650M XT manages 19.79 TFLOPS at a 2:1 ratio. Half-precision workloads narrow the gap but still favor the L4.

Architecture Differences

These chips come from consecutive GPU generations with fundamentally different missions. The L4 uses the AD104 die on NVIDIA's Ada Lovelace architecture, fabricated on TSMC's 5 nm process. The 6650M XT uses the smaller Navi 23 die on RDNA 2.0, built on TSMC's 7 nm process. The node difference shows up clearly in the density figures: 121.8M transistors per mm² for the L4 versus 46.7M per mm² for the AMD part.

The L4 packs 35,800 million transistors into a 294 mm² die, more than three times the 11,060 million transistors of the 6650M XT's 237 mm² die. That transistor budget translates into 7424 shading units, 240 TMUs, 80 ROPs, 60 RT cores, and critically, 240 tensor cores. The 6650M XT has 2048 shading units, 128 TMUs, 64 ROPs, and 32 RT cores, with no tensor cores listed at all. For machine learning and AI inference workloads, that tensor core count is arguably the single biggest differentiator in this matchup.

Power and physical characteristics diverge just as sharply. The L4 is a 72 W single-slot card measuring 169 mm long and 56 mm tall, with no power connectors, running on PCIe 4.0 x16 with a suggested 250 W system supply. The 6650M XT is an integrated mobile part drawing 120 W over PCIe 4.0 x8. Both support DirectX 12 Ultimate (12_2), OpenGL 4.6, and Vulkan 1.4, so API support is identical. Both come from TSMC fabs.

Their lineages differ too. The L4 is an active product in the Server Ada generation, sandwiched between the Server Ampere predecessor and Server Hopper successor, released on 2023-03-20. The 6650M XT belongs to the RX 6000M mobile family, succeeded the Polaris Mobile line, has no listed successor, was released on 2022-01-03, and carries an end-of-life production status.

The Verdict

If the workload is compute, inference, or anything that benefits from tensor cores and large memory capacity, the L4 is the clear pick. The data shows an 83.1% OpenCL win, triple the FP32 throughput, three times the memory, and a competitive position against RTX 3090 Ti-class hardware, all within a 72 W single-slot envelope. It is a server accelerator, and the numbers read like one.

The 6650M XT makes sense only where its mobile heritage matters. It is the pick if display output is required, since the L4 has none, and its higher clocks and near-parity pixel fill rate keep it relevant for mobile graphics tasks. It holds a 91st percentile position against a rival set of other mobile and professional parts. But it is end-of-life, draws more power (120 W versus 72 W), and loses the one benchmark they share. For pure performance per watt in compute, the L4's advantage is overwhelming: more work at lower power draw.

One caveat from the data: with only a single overlapping benchmark, the comparison rests heavily on OpenCL. The L4's Vulkan score of 121306 has no counterpart entry for the AMD card, so graphics API performance remains only partially characterized.

FAQ

Q: Which GPU wins in benchmarks?

A: The NVIDIA L4. In the shared Geekbench OpenCL test it scores 140838 versus 76904 for the RX 6650M XT, an 83.1% lead. The L4 sits in the 95th percentile of all GPUs; the 6650M XT sits in the 91st.

Q: How much VRAM does each GPU have?

A: The L4 has 24 GB of GDDR6 on a 192-bit bus with 300.1 GB/s of bandwidth. The 6650M XT has 8 GB of GDDR6 on a 128-bit bus with 256.0 GB/s of bandwidth.

Q: Which is more power efficient?

A: On paper, the L4. It has a 72 W TDP compared to 120 W for the 6650M XT, while delivering substantially higher benchmark scores and FP32 throughput.

Q: Does either GPU have tensor cores?

A: The L4 has 240 tensor cores. The 6650M XT has no tensor cores listed in the database, making the L4 the clear choice for AI and machine learning workloads.

Q: Can these GPUs drive a display?

A: The 6650M XT can, with outputs described as portable device dependent. The L4 has no display outputs and functions purely as a compute accelerator.

Q: Are both GPUs still in production?

A: No. The L4 is listed as active, released 2023-03-20. The 6650M XT is listed as end-of-life, released 2022-01-03.

Specification Differences

| Field | NVIDIA L4 | AMD Radeon RX 6650M XT |

|---|---|---|

| Chip | AD104 | Navi 23 |

| Architecture | Ada Lovelace | RDNA 2.0 |

| Generation | Server Ada (Lxx) | Navi Mobile (RX 6000M) |

| Process node | 5 nm | 7 nm |

| Transistors | 35,800 million | 11,060 million |

| Die size | 294 mm² | 237 mm² |

| Transistor density | 121.8M / mm² | 46.7M / mm² |

| Base clock | 795 MHz | 2068 MHz |

| Boost clock | 2040 MHz | 2416 MHz |

| Game clock | Not listed | 2162 MHz |

| Memory clock | 1563 MHz (12.5 Gbps effective) | 2000 MHz (16 Gbps effective) |

| Memory size | 24 GB GDDR6 | 8 GB GDDR6 |

| Bus width | 192 bit | 128 bit |

| Bandwidth | 300.1 GB/s | 256.0 GB/s |

| Shading units | 7424 | 2048 |

| TMUs | 240 | 128 |

| ROPs | 80 | 64 |

| RT cores | 60 | 32 |

| Tensor cores | 240 | None listed |

| FP32 | 30.29 TFLOPS | 9.896 TFLOPS |

| FP16 | 30.29 TFLOPS (1:1) | 19.79 TFLOPS (2:1) |

| Pixel rate | 163.2 GPixel/s | 154.6 GPixel/s |

| Texture rate | 489.6 GTexel/s | 309.2 GTexel/s |

| TDP | 72 W | 120 W |

| Slot width | Single-slot | IGP |

| Suggested PSU | 250 W | Not listed |

| Bus interface | PCIe 4.0 x16 | PCIe 4.0 x8 |

| Display outputs | No outputs | Portable device dependent |

| Dimensions | 169 mm x 56 mm | Not listed |

| Production status | Active | End-of-life |

| Release date | 2023-03-20 | 2022-01-03 |

| Predecessor | Server Ampere | Polaris Mobile |

| Successor | Server Hopper | None listed |

| Percentile vs all GPUs | 95 | 91 |

| Average benchmark score | 131072 | 76904 |

| Geekbench OpenCL | 140838 | 76904 |

| Geekbench Vulkan | 121306 | Not listed |