AMD Instinct MI300X vs NVIDIA GeForce RTX 3090 Ti Comparison

Where Each One Wins

The benchmark data splits cleanly along workload lines. The AMD Instinct MI300X dominates the only directly comparable compute metric, Geekbench OpenCL, with a score of 317,994 against the NVIDIA GeForce RTX 3090 Ti's 174,441. That is an 82.3% advantage, a margin that positions the MI300X as the clear choice for OpenCL compute workloads. Its average benchmark score of 317,994 also places it in the 100th percentile of all GPUs in the database, meaning no recorded GPU scores higher on average. In contrast, the RTX 3090 Ti's average sits at 131,938, good for the 95th percentile.

The NVIDIA card, however, is the only one of the two with any recorded graphics API support. The database lists DirectX 12 Ultimate (12_2), OpenGL 4.6, and Vulkan 1.4 for the RTX 3090 Ti, while the MI300X lists N/A for all three. The RTX 3090 Ti also has display outputs: one HDMI 2.1 and three DisplayPort 1.4a. The MI300X has no outputs. So for any interactive graphics, rendering, or display-connected workload, the RTX 3090 Ti is the only functional option in this comparison.

The MI300X wins the raw compute contest outright. The RTX 3090 Ti wins by default in every graphics-oriented scenario. There is no overlap where both cards can plausibly serve the same task, which makes the use-case split unusually stark.

FAQ

Q: Which GPU has the higher OpenCL score?

A: The AMD Instinct MI300X scores 317,994 in Geekbench OpenCL, versus 174,441 for the NVIDIA GeForce RTX 3090 Ti, a difference of 82.3%.

Q: Can the AMD Instinct MI300X output video to a display?

A: No. The database records no display outputs for the MI300X, and its DirectX, OpenGL, and Vulkan support are all listed as N/A.

Q: What is the memory capacity of each card?

A: The MI300X has 192 GB of HBM3 memory on an 8192-bit bus, while the RTX 3090 Ti has 24 GB of GDDR6X on a 384-bit bus.

Q: How do their memory bandwidth figures compare?

A: The MI300X delivers 5.32 TB/s, more than five times the RTX 3090 Ti's 1.01 TB/s.

Q: Which card has a higher transistor count?

A: The MI300X contains 153,000 million transistors on a 1017 mm² die, while the RTX 3090 Ti has 28,300 million transistors on a 628 mm² die.

Q: Is the RTX 3090 Ti still in production?

A: No, the database marks it as end-of-life. The MI300X has no production status listed.

Head-to-Head Benchmarks

The sole head-to-head benchmark in the database is Geekbench OpenCL, and it is not close. The AMD Instinct MI300X posts 317,994, the NVIDIA GeForce RTX 3090 Ti posts 174,441. The delta is 82.3% in favor of AMD. To frame that differently, the MI300X's score is roughly 1.82 times the RTX 3090 Ti's score. In percentile terms, the MI300X sits at 100th among all GPUs, while the RTX 3090 Ti sits at 95th.

The MI300X's nearest rivals in the database help contextualize that number. The NVIDIA H200 NVL averages 334,891, which is 5% higher than the MI300X. The NVIDIA B200 averages 345,482, 8% higher. The NVIDIA L40S trails at 295,763, which is 7.5% lower than the MI300X. The NVIDIA RTX 6000 Ada Generation is 10.7% lower at 287,237. So the MI300X is not the single fastest accelerator in the database, but it sits in a tight cluster with the H200 NVL and B200, all well above the RTX 3090 Ti's range.

For the RTX 3090 Ti, its nearest rivals are far less exotic. The NVIDIA L4 averages 131,072, a 0.7% gap. The NVIDIA RTX 4000 Ada Generation averages 135,218, 2.4% higher. The NVIDIA A10M averages 135,230, also 2.4% higher. The AMD Radeon PRO W6800 averages 135,396, 2.6% higher. The RTX 3090 Ti's average score of 131,938 places it in the middle of a cluster of professional and workstation cards, none of which approach the MI300X's compute output. The only head-to-head result, therefore, tells a simple story: for OpenCL compute, the MI300X is in a different class entirely.

Specification Differences

The two cards differ in nearly every core specification. The MI300X has 19,456 shading units, 1,216 texture mapping units, and zero ROPs. The RTX 3090 Ti has 10,752 shading units, 336 TMUs, and 112 ROPs. The MI300X's texture rate is 2,553.6 GTexel/s, while the RTX 3090 Ti manages 625.0 GTexel/s. The pixel rate tells the opposite story: the MI300X records 0 MPixel/s, the RTX 3090 Ti records 208.3 GPixel/s.

Clock behavior also differs. The MI300X has a base clock of 1000 MHz and a boost of 2100 MHz. The RTX 3090 Ti has a base of 1560 MHz and a boost of 1860 MHz. Memory clocks are near parity in raw frequency, 1300 MHz for the MI300X versus 1313 MHz for the RTX 3090 Ti, but the effective data rates diverge: 5.2 Gbps for the MI300X versus 21 Gbps for the RTX 3090 Ti. This is due to the different memory types and bus widths.

Power requirements differ substantially. The MI300X has a TDP of 750 W and a suggested PSU of 1150 W. The RTX 3090 Ti has a TDP of 450 W and a suggested PSU of 850 W. The MI300X uses an OAM module form factor with no power connectors, while the RTX 3090 Ti is a triple-slot card with a single 16-pin connector. The bus interfaces differ as well: the MI300X uses PCIe 5.0 x16, the RTX 3090 Ti uses PCIe 4.0 x16.

The RTX 3090 Ti has physical dimensions of 336 mm in length, 140 mm in height, and 61 mm in width. The MI300X has no dimensions listed in the database. The RTX 3090 Ti also carries a launch MSRP of 1,999 USD. The MI300X has no launch MSRP recorded.

Architecture Differences

The MI300X is built on CDNA 3.0, AMD's compute-focused architecture, implemented on a 5 nm TSMC process. The chip, codenamed Aqua Vanjaram, contains 153,000 million transistors on a 1017 mm² die, yielding a transistor density of 150.4 million per mm². It belongs to the Instinct (MIx) generation, and its predecessor is listed as Radeon Instinct. The MI300X has no RT cores or tensor cores listed in the database, reinforcing its role as a pure compute accelerator.

The RTX 3090 Ti is built on Ampere, NVIDIA's consumer and professional architecture, on an 8 nm Samsung process. The GA102 chip contains 28,300 million transistors on a 628 mm² die, for a density of 45.1 million per mm². It belongs to the GeForce 30-series, with the GeForce 20 as its predecessor and GeForce 40 as its successor. Unlike the MI300X, it includes 84 RT cores and 336 tensor cores, giving it hardware support for ray tracing and tensor workloads. Its API support extends to DirectX 12 Ultimate (12_2), OpenGL 4.6, and Vulkan 1.4, while the MI300X lists N/A for all three.

Memory architecture is another clear divider. The MI300X uses 192 GB of HBM3 across an 8192-bit bus, producing 5.32 TB/s of bandwidth. The RTX 3090 Ti uses 24 GB of GDDR6X across a 384-bit bus, producing 1.01 TB/s. The MI300X's memory configuration is characteristic of an accelerator designed for large model residency, while the RTX 3090 Ti's smaller, faster-per-pin GDDR6X setup suits a consumer graphics card. The release dates also differ: the MI300X launched on 2023-12-05, the RTX 3090 Ti on 2022-01-26. The RTX 3090 Ti is marked end-of-life; the MI300X has no production status listed.

The Verdict

The data supports a straightforward conclusion. For OpenCL compute, the AMD Instinct MI300X is overwhelmingly faster, with a 317,994 score against the RTX 3090 Ti's 174,441, an 82.3% lead. It also carries 192 GB of HBM3 memory with 5.32 TB/s of bandwidth, 8 times the capacity and over 5 times the bandwidth of the RTX 3090 Ti. Its 100th-percentile average score places it at the top of the database, above the RTX 3090 Ti's 95th percentile. Any workload that fits within OpenCL and can use massive memory capacity should favor the MI300X.

The NVIDIA GeForce RTX 3090 Ti is the only card here with graphics capabilities. It has display outputs, full DirectX 12 Ultimate, OpenGL 4.6, and Vulkan 1.4 support, plus 84 RT cores and 336 tensor cores. The MI300X has none of these. For any rendering, ray tracing, or display-connected task, the RTX 3090 Ti is the only viable option. Its 24 GB of GDDR6X and 1.01 TB/s bandwidth are modest next to the MI300X, but they are irrelevant if the MI300X cannot run the workload at all.

Who should pick which: if the task is compute-heavy, memory-hungry, and does not require a display, the MI300X is the clear choice. If the task requires graphics output, API compatibility, or consumer software support, the RTX 3090 Ti is the only option in this comparison. The two cards do not compete for the same buyer. The benchmark data simply confirms that they occupy entirely different segments.