AMD Instinct MI300 vs AMD Radeon RX 7800 XT Comparison

FAQ

Q: What is the primary architectural difference between the AMD Instinct MI300 and the AMD Radeon RX 7800 XT?

A: The MI300 uses the CDNA 3.0 architecture on the Aqua Vanjaram chip, while the RX 7800 XT uses RDNA 3.0 on the Navi 32 chip. The MI300 is an accelerator with no display outputs, whereas the RX 7800 XT is a graphics card with 1x HDMI 2.1a and 3x DisplayPort 2.1 outputs.

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

A: The MI300 has 128 GB of HBM3 memory on an 8192-bit bus with 5.32 TB/s bandwidth. The RX 7800 XT has 16 GB of GDDR6 memory on a 256-bit bus with 624.1 GB/s bandwidth.

Q: What is the FP32 compute performance difference?

A: The MI300 delivers 47.87 TFLOPS FP32, while the RX 7800 XT delivers 37.32 TFLOPS FP32. Both achieve FP16 at a 1:1 ratio with the same TFLOPS numbers.

Q: What is the power consumption of each card?

A: The MI300 has a TDP of 600 W and a suggested PSU of 1000 W. The RX 7800 XT has a TDP of 263 W and a suggested PSU of 600 W. Both use 2x 8-pin power connectors.

Q: Which card has a higher transistor density?

A: The MI300 has a transistor density of 150.4M per mm², while the RX 7800 XT has 81.2M per mm². The MI300 packs 153,000 million transistors on a 1017 mm² die, versus 28,100 million on a 346 mm² die for the RX 7800 XT.

Q: What benchmark data exists for these cards?

A: The RX 7800 XT has ten recorded benchmark scores including 3DMark Steel Nomad (4157), Geekbench Vulkan (54228), and Passmark G3D (24176), with an average score of 11627. The MI300 has no recorded benchmark scores and a 50th percentile ranking, while the RX 7800 XT sits at the 51st percentile.

Architecture Differences

The MI300 and RX 7800 XT represent two distinct design philosophies from AMD. The MI300 is built on the CDNA 3.0 architecture, optimized for compute acceleration, while the RX 7800 XT uses RDNA 3.0, designed for graphics rendering. Both are fabricated on TSMC's 5 nm process, but the similarities end there.

The MI300's Aqua Vanjaram chip is a massive 1017 mm² die with 153,000 million transistors, achieving a density of 150.4M per mm². The RX 7800 XT's Navi 32 chip is considerably smaller at 346 mm² with 28,100 million transistors, resulting in a density of 81.2M per mm². This density difference reflects the MI300's focus on compute-oriented logic blocks.

Memory architecture diverges sharply. The MI300 uses 128 GB of HBM3 with an 8192-bit bus, delivering 5.32 TB/s of bandwidth. The RX 7800 XT uses 16 GB of GDDR6 on a 256-bit bus, providing 624.1 GB/s. The MI300's bandwidth is over eight times higher, a critical factor for data-intensive workloads.

The MI300 has 14,080 shading units and 880 texture mapping units, but zero ROPs and no display outputs. It also reports a pixel rate of 0 MPixel/s. The RX 7800 XT has 3,840 shading units, 240 TMUs, and 96 ROPs, with a pixel rate of 233.3 GPixel/s and 60 ray tracing cores. The MI300 includes no ray tracing cores in the database.

Clock speeds favor the RX 7800 XT. Its base clock is 1295 MHz with a boost of 2430 MHz and a game clock of 2124 MHz. The MI300 runs at 1000 MHz base and 1700 MHz boost. Memory clocks also differ: the MI300 runs at 1300 MHz (5.2 Gbps effective), while the RX 7800 XT runs at 2438 MHz (19.5 Gbps effective).

The MI300 supports PCIe 5.0 x16, while the RX 7800 XT uses PCIe 4.0 x16. The MI300 has no API support listed (DirectX, OpenGL, Vulkan all N/A), while the RX 7800 XT supports DirectX 12 Ultimate (12_2), OpenGL 4.6, and Vulkan 1.4. The MI300 was released on 2023-01-03, and the RX 7800 XT followed on 2023-09-05.

Head-to-Head Benchmarks

The database contains no head-to-head benchmark results between the MI300 and RX 7800 XT. The only recorded benchmark scores belong to the RX 7800 XT, which has ten entries. The MI300 has zero benchmark scores and an average benchmark score of zero.

The RX 7800 XT's benchmark results show a wide spread across tests. Its highest score is 54,228 in Geekbench Vulkan, followed by 24,176 in Passmark G3D and 18,290 in Geekbench OpenCL. In 3DMark Steel Nomad DX12, it scores 4,157. Passmark sub-tests show 304 in DirectX 9, 249 in DirectX 11, 121 in DirectX 10, and 93 in DirectX 12. Passmark G2D scores 1,177, and GPU Compute scores 13,473.

The RX 7800 XT's average benchmark score of 11,627 places it at the 51st percentile of all GPUs. Its nearest rivals in the database include the NVIDIA GeForce GTX 1660 with an average score of 11,680 (0.5% higher), the AMD Radeon Pro 5500M at 11,528 (0.9% lower), the NVIDIA Tesla K20c at 11,479 (1.3% lower), and the AMD Radeon RX 6500 XT at 11,842 (1.8% higher).

Since the MI300 has no benchmark data, direct numerical comparison is impossible. The percentile rankings show the MI300 at 50th percentile versus the RX 7800 XT at 51st, a negligible difference, but this reflects the absence of scores for the MI300 rather than actual performance equivalence. The compute specifications suggest the MI300 has significantly higher raw throughput, but the database does not provide measured results to confirm this.

Specification Differences

The two cards differ across nearly every specification category. Process node is identical at 5 nm from TSMC, but die size differs substantially: 1017 mm² for the MI300 versus 346 mm² for the RX 7800 XT. Transistor count is 153,000 million versus 28,100 million, and density is 150.4M per mm² versus 81.2M per mm².

Clock speeds show the RX 7800 XT running faster. Its base clock is 1295 MHz versus 1000 MHz, boost is 2430 MHz versus 1700 MHz, and it has a game clock of 2124 MHz that the MI300 lacks. Memory clocks are 2438 MHz (19.5 Gbps) for the RX 7800 XT versus 1300 MHz (5.2 Gbps) for the MI300.

Memory configuration differs completely: 128 GB HBM3 on 8192-bit bus versus 16 GB GDDR6 on 256-bit bus. Bandwidth is 5.32 TB/s versus 624.1 GB/s. The MI300 has 14,080 shading units, 880 TMUs, and 0 ROPs. The RX 7800 XT has 3,840 shading units, 240 TMUs, and 96 ROPs, plus 60 RT cores.

Texture rate is 1,496.0 GTexel/s for the MI300 versus 583.2 GTexel/s for the RX 7800 XT. Pixel rate is 0 MPixel/s for the MI300 versus 233.3 GPixel/s for the RX 7800 XT. FP32 compute is 47.87 TFLOPS versus 37.32 TFLOPS, with both at 1:1 FP16.

Power requirements favor the RX 7800 XT: 263 W TDP with 600 W PSU suggestion versus 600 W TDP with 1000 W PSU suggestion. Both use 2x 8-pin connectors. The RX 7800 XT is dual-slot with a 50 mm width, while the MI300 has no slot width listed. Both are 267 mm long and 111 mm high.

Bus interface differs: PCIe 5.0 x16 for the MI300 versus PCIe 4.0 x16 for the RX 7800 XT. Display outputs exist only on the RX 7800 XT. API support is present only on the RX 7800 XT. The RX 7800 XT has an active production status, while the MI300's status is not listed. The MI300 lists a predecessor of Radeon Instinct, while the RX 7800 XT lists Navi II as predecessor and Navi IV as successor.

Where Each One Wins

The MI300 wins in raw compute capacity. Its 47.87 TFLOPS FP32 output exceeds the RX 7800 XT's 37.32 TFLOPS by roughly 28%. Texture rate is substantially higher at 1,496.0 GTexel/s versus 583.2 GTexel/s. Memory bandwidth of 5.32 TB/s dwarfs the 624.1 GB/s available on the RX 7800 XT, and the 128 GB capacity allows working sets that would never fit in 16 GB.

The MI300 also leads in shading units (14,080 versus 3,840) and TMUs (880 versus 240). Its PCIe 5.0 x16 interface provides double the bandwidth of the RX 7800 XT's PCIe 4.0 x16. For compute workloads that scale with memory capacity and bandwidth, such as large model training or scientific simulation, the MI300's specifications indicate a clear advantage.

The RX 7800 XT wins in graphics-specific features. It has 96 ROPs and 60 ray tracing cores, both absent from the MI300. Its pixel rate of 233.3 GPixel/s enables rasterization, while the MI300 reports zero. Display outputs on the RX 7800 XT allow direct monitor connection, whereas the MI300 has none.

Clock speeds favor the RX 7800 XT, with boost at 2430 MHz versus 1700 MHz. This higher clock rate, combined with the graphics pipeline, makes it suitable for frame rendering. The RX 7800 XT's API support (DirectX 12 Ultimate, OpenGL 4.6, Vulkan 1.4) enables gaming and graphics applications, while the MI300 lists no graphics API support.

Power efficiency favors the RX 7800 XT. Its 263 W TDP delivers 37.32 TFLOPS, while the MI300 requires 600 W for 47.87 TFLOPS. The RX 7800 XT achieves 141.9 GFLOPS per watt versus 79.8 GFLOPS per watt for the MI300. The RX 7800 XT also has a lower PSU requirement of 600 W versus 1000 W.

The RX 7800 XT has recorded benchmark data confirming its performance in graphics tests. Its 54,228 Geekbench Vulkan score and 24,176 Passmark G3D score demonstrate real-world results. The MI300 has no measured scores in the database.

The Verdict

The data presents two specialized tools rather than direct competitors. The MI300 is an accelerator designed for compute workloads, evidenced by its massive 128 GB HBM3 pool, 8192-bit bus, 5.32 TB/s bandwidth, and absence of display outputs or graphics APIs. Its 47.87 TFLOPS FP32 and 1,496.0 GTexel/s texture rate indicate heavy number-crunching capability, but the 600 W TDP and 1000 W PSU requirement make it a data-center-oriented part.

The RX 7800 XT is a graphics card through and through. Its 96 ROPs, 60 RT cores, 233.3 GPixel/s pixel rate, and 3x DisplayPort 2.1 outputs confirm its role in rendering frames. The 263 W TDP and 600 W PSU suggestion place it in the consumer desktop segment. Its benchmark scores, including 4,157 in 3DMark Steel Nomad and 54,228 in Geekbench Vulkan, provide measurable graphics performance.

Users needing compute throughput for memory-bound workloads should consider the MI300, as its 128 GB capacity and 5.32 TB/s bandwidth are unmatched by the RX 7800 XT's 16 GB and 624.1 GB/s. Users needing a graphics card with ray tracing, display outputs, and API compatibility should choose the RX 7800 XT, as the MI300 offers none of those features.

The RX 7800 XT's 51st percentile ranking, based on an average score of 11,627, places it near the NVIDIA GeForce GTX 1660 (11,680, 0.5% higher) and AMD Radeon RX 6500 XT (11,842, 1.8% higher). The MI300's 50th percentile reflects no benchmark data, so direct comparison is not possible from measurements.

The release dates differ by roughly eight months, with the MI300 launching on 2023-01-03 and the RX 7800 XT on 2023-09-05. Both use TSMC 5 nm, but the MI300's 1017 mm² die is nearly three times larger than the RX 7800 XT's 346 mm² die. The MI300's transistor density of 150.4M per mm² versus 81.2M per mm² indicates a more logic-dense design.

The choice depends on workload. The MI300 targets compute acceleration with no graphics capability, while the RX 7800 XT targets graphics rendering with no accelerator-level memory capacity. The database shows no overlap in their intended functions. The RX 7800 XT has a launch MSRP of 499 USD, but no pricing data exists for the MI300.