NVIDIA GeForce RTX 3080 Ti Mobile vs NVIDIA GeForce RTX 3090 Comparison

The NVIDIA GeForce RTX 3090 and the NVIDIA GeForce RTX 3080 Ti Mobile represent two extremes of the Ampere architecture: a desktop flagship designed for maximum throughput versus a mobile part engineered for a constrained power envelope. The benchmark data shows a clear overall winner, but the single exception to that trend reveals a significant performance quirk. Across ten head-to-head tests, the RTX 3090 secures nine wins, while the RTX 3080 Ti Mobile claims one decisive victory.

Head-to-Head Benchmarks

The most lopsided results favor the desktop RTX 3090 in compute-heavy workloads. In the Passmark GPU Compute test, the RTX 3090 scores 15,356 against 8,471 for the mobile chip, a massive 81.3% advantage. This delta is nearly mirrored in the 3DMark Steel Nomad DX12 test, where the RTX 3090’s score of 5,118 eclipses the 2,869 of the RTX 3080 Ti Mobile by 78.4%. These two results indicate that the desktop card’s raw shader and compute throughput is in a different class entirely.

The gap narrows considerably in synthetic graphics tests, but the RTX 3090 still leads by significant margins. In Passmark G3D, the RTX 3090 posts 26,645 versus 19,288, a 38.1% lead. The Geekbench OpenCL score of 172,758 for the RTX 3090 is 46.6% higher than the 117,866 achieved by the mobile part. Legacy DirectX tests show a consistent pattern: the RTX 3090 leads by 38.9% in DirectX 10 (182 vs 131), 34.1% in DirectX 11 (220 vs 164), and 33.3% in DirectX 9 (268 vs 201). Even the Passmark DirectX 12 score, while the smallest win for the desktop card, still shows a 25% advantage (110 vs 88).

The most notable outlier is Geekbench Vulkan. Here, the RTX 3080 Ti Mobile scores 107,502, which is nearly double the RTX 3090’s 53,927, resulting in a 49.8% lead for the mobile GPU. This is a stark reversal of the trend seen in every other test and suggests that the mobile part’s driver or hardware implementation has a particular strength in this specific Vulkan workload. The RTX 3090 also wins the Passmark G2D test (1,063 vs 818, a 30% gap), which measures 2D performance.

Architecture Differences

Both GPUs are built on the Ampere architecture and use Samsung’s 8 nm process node, but they diverge sharply in their physical implementation. The RTX 3090 uses the GA102 chip with 28,300 million transistors on a 628 mm² die, yielding a transistor density of 45.1M per mm². The RTX 3080 Ti Mobile uses the smaller GA103 chip, with 22,000 million transistors on a 496 mm² die, resulting in a density of 44.4M per mm². The desktop chip is physically larger and packs more transistors, which directly translates to its higher core counts.

The RTX 3090 features 10,496 shading units, 328 TMUs, and 112 ROPs, alongside 82 RT cores and 328 tensor cores. The mobile part is significantly cut down, featuring 7,424 shading units, 232 TMUs, 96 ROPs, 58 RT cores, and 232 tensor cores. This reduction in core counts is the primary driver of the performance gap observed in most benchmarks. Clock speeds also differ substantially: the RTX 3090 has a base clock of 1395 MHz and a boost of 1695 MHz, while the RTX 3080 Ti Mobile operates at a much lower 810 MHz base and 1260 MHz boost. The desktop card’s higher clocks compound its core-count advantage.

Memory configurations are another major differentiator. The RTX 3090 comes with 24 GB of GDDR6X on a 384-bit bus, delivering 936.2 GB/s of bandwidth. The RTX 3080 Ti Mobile is equipped with 16 GB of GDDR6 on a 256-bit bus, providing 512.0 GB/s. The desktop card has nearly double the memory bandwidth, which is crucial for high-resolution textures and compute workloads. The memory clocks also differ, with the RTX 3090 running at 1219 MHz (19.5 Gbps effective) versus 2000 MHz (16 Gbps effective) for the mobile part.

Power and physical dimensions further separate these two. The RTX 3090 has a TDP of 350 W and requires a triple-slot cooler and a 750 W power supply. The RTX 3080 Ti Mobile has a TDP of 115 W and uses no dedicated power connectors, as it is designed to draw power from a laptop’s motherboard. The RTX 3090 measures 336 mm in length, while the mobile GPU has no listed dimensions, being a BGA component. The desktop card’s display outputs are 1x HDMI 2.1 and 3x DisplayPort 1.4a, while the mobile part’s outputs are listed as portable-device dependent.

The Verdict

The data is unambiguous for most workloads: the NVIDIA GeForce RTX 3090 is the far more powerful GPU. It wins nine of ten benchmarks, with leads ranging from 25% to 81.3%. The average benchmark score reflects this, with the RTX 3090 at 27,565 compared to 25,740 for the RTX 3080 Ti Mobile, a 7.1% difference. The desktop card also holds a higher percentile rank among all GPUs, sitting at the 73rd percentile versus the 71st for the mobile part. Its nearest rivals include the AMD Radeon RX 6700 XT and the NVIDIA GeForce RTX 4070 Mobile, both within 0.5% of its average score, while the RTX 3080 Ti Mobile sits alongside the AMD Radeon RX 6700M.

The singular exception is the Geekbench Vulkan test, where the RTX 3080 Ti Mobile’s score of 107,502 is nearly double that of the RTX 3090. This indicates that the mobile GPU has a specific advantage in this API, which could be relevant for certain Vulkan-based applications. However, this single data point does not offset the overwhelming performance lead of the RTX 3090 in all other measured areas. For a user prioritizing raw compute, 3D rendering, or DirectX-based gaming, the RTX 3090 is the clear choice. For a workload that is heavily optimized for Vulkan, the mobile part may offer a surprising edge.

FAQ

Q: Which GPU has a higher average benchmark score?

A: The NVIDIA GeForce RTX 3090 has an average benchmark score of 27,565, which is higher than the 25,740 average of the NVIDIA GeForce RTX 3080 Ti Mobile.

Q: In which benchmark does the RTX 3080 Ti Mobile outperform the RTX 3090?

A: The RTX 3080 Ti Mobile wins the Geekbench Vulkan test, scoring 107,502 against the RTX 3090’s 53,927, a deltaPct of -49.8% for the desktop card.

Q: What is the largest performance delta between the two GPUs?

A: The largest delta is in the Passmark GPU Compute test, where the RTX 3090 leads by 81.3% with a score of 15,356 versus 8,471 for the RTX 3080 Ti Mobile.

Q: How much memory and what type does each GPU have?

A: The RTX 3090 has 24 GB of GDDR6X memory, while the RTX 3080 Ti Mobile has 16 GB of GDDR6 memory.

Q: What are the TDPs of these two GPUs?

A: The RTX 3090 has a TDP of 350 W, while the RTX 3080 Ti Mobile has a TDP of 115 W.

Q: Which GPU has more RT cores?

A: The RTX 3090 has 82 RT cores, compared to 58 RT cores on the RTX 3080 Ti Mobile.

Where Each One Wins

The RTX 3090 dominates in compute and DirectX workloads. It wins the Passmark GPU Compute test by 81.3%, the 3DMark Steel Nomad DX12 test by 78.4%, and the Geekbench OpenCL test by 46.6%. It also leads in all legacy DirectX tests (9, 10, 11, and 12), with advantages ranging from 25% to 38.9%. For users running general-purpose GPU compute, 3D rendering, or older DirectX titles, the RTX 3090 is the superior performer. Its higher texture rate of 556.0 GTexel/s and pixel rate of 189.8 GPixel/s also contribute to its wins in the G3D test.

The RTX 3080 Ti Mobile’s only win is the Geekbench Vulkan test, where it scores 107,502 versus 53,927. This test measures performance under the Vulkan API, and the mobile GPU’s lead is substantial. This suggests that for applications or games that are specifically optimized for Vulkan, the RTX 3080 Ti Mobile could provide a better experience. It also has a lower TDP, meaning it can be integrated into portable devices without the power and cooling requirements of the desktop card.

Specification Differences

The two GPUs differ in nearly every major specification. The RTX 3090 uses the GA102 chip, while the RTX 3080 Ti Mobile uses the GA103. The desktop card has 28,300 million transistors on a 628 mm² die, while the mobile chip has 22,000 million on a 496 mm² die. Core counts differ significantly: the RTX 3090 has 10,496 shading units, 328 TMUs, and 112 ROPs, versus 7,424 shading units, 232 TMUs, and 96 ROPs for the mobile part. RT and tensor cores also differ (82/328 vs 58/232).

Clock speeds are much higher on the RTX 3090, with a base of 1395 MHz and boost of 1695 MHz, compared to 810 MHz and 1260 MHz on the mobile chip. Memory is a major difference: the RTX 3090 has 24 GB of GDDR6X on a 384-bit bus with 936.2 GB/s bandwidth, while the RTX 3080 Ti Mobile has 16 GB of GDDR6 on a 256-bit bus with 512.0 GB/s. The RTX 3090’s TDP is 350 W, requiring a triple-slot cooler and a 750 W PSU, while the mobile part has a TDP of 115 W and no power connectors. The FP32 compute is also different, with the RTX 3090 achieving 35.58 TFLOPS versus 18.71 TFLOPS for the mobile GPU.