AMD Instinct MI300A vs AMD Instinct MI300X Comparison

The Verdict

The database records only one benchmark result for this pair, and it belongs to the AMD Instinct MI300X. The MI300A has no recorded benchmark score, placing it at the 50th percentile of all GPUs with an average benchmark score of zero. The MI300X, by contrast, sits at the 100th percentile with an average benchmark score of 317,994 in Geekbench OpenCL. Any practical comparison between the two accelerators must therefore rely on the MI300X’s measured performance and the architectural specifications that define both parts.

The MI300X is the clear choice for workloads that depend on raw compute throughput and memory capacity. It delivers 81.72 TFLOPS of FP32 performance and 81.72 TFLOPS of FP16 (1:1) performance, paired with 192 GB of HBM3 memory. The MI300A offers 61.29 TFLOPS of FP32 and the same 5.32 TB/s memory bandwidth, but only 128 GB of memory. For applications that scale with memory footprint, such as large model inference or dense matrix operations, the MI300X’s additional 64 GB provides a decisive capacity advantage.

The MI300A, however, is not without a role. Its lower shading unit count (14,592 versus 19,456) and reduced texture rate (1,915.2 GTexel/s versus 2,553.6 GTexel/s) indicate a part designed for a different balance of compute and memory. The MI300A still matches the MI300X in memory bandwidth, bus width, and clock speeds, so memory-bound workloads that fit within 128 GB may see similar throughput. But the recorded data shows no benchmark wins for the MI300A, so any advantage would be speculative rather than measured.

In short, the MI300X is the only member of this pair with verified performance data, and that data places it among the top accelerators in the database. The MI300A remains a capable alternative on paper, but without benchmark scores, its real-world standing cannot be confirmed from the available records.

Architecture Differences

Both accelerators share the same fundamental design. They use the Aqua Vanjaram chip, built on CDNA 3.0 architecture, fabricated on TSMC’s 5 nm process. Both contain 153,000 million transistors on a 1017 mm² die, yielding a transistor density of 150.4M per mm². They share the same base clock of 1000 MHz and boost clock of 2100 MHz, with memory clocked at 1300 MHz and 5.2 Gbps effective. Both use HBM3 memory with an 8192-bit bus and 5.32 TB/s bandwidth.

The differences emerge in the execution resources. The MI300X packs 19,456 shading units, 1,216 texture mapping units, and 1,216 TMUs. The MI300A reduces these to 14,592 shading units and 912 TMUs. Neither part has ROPs, with both recording 0 MPixel/s pixel rate. Neither has ray tracing cores or tensor cores listed, and both report N/A for DirectX, OpenGL, and Vulkan support, with no display outputs.

Memory capacity is the second major divergence. The MI300X carries 192 GB of HBM3, while the MI300A carries 128 GB. Both share the same 8192-bit bus and 5.32 TB/s bandwidth, so the capacity difference does not affect raw throughput. The MI300X also lists FP16 performance at 81.72 TFLOPS (1:1), while the MI300A lists no FP16 figure, suggesting the MI300X has explicit FP16 capability or at least a documented one.

Both parts consume 750 W TDP, use an OAM Module slot width, have no power connectors, and recommend a 1150 W power supply. Both use PCIe 5.0 x16 as the bus interface. Both were released on the same date, December 5, 2023, and both succeed the Radeon Instinct line. No successor is recorded for either.

Head-to-Head Benchmarks

The database contains no direct head-to-head benchmark entries for the MI300A versus the MI300X. The MI300A has zero wins and the MI300X has zero wins in this pairing. However, the MI300X has one recorded benchmark: Geekbench OpenCL with a score of 317,994. That score places the MI300X at the 100th percentile of all GPUs, a remarkable position that indicates it outperforms virtually every other recorded accelerator in the database.

The nearest rivals to the MI300X provide context. The NVIDIA H200 NVL scores 334,891, which is 5% higher than the MI300X. The NVIDIA B200 scores 345,482, which is 8% higher. The NVIDIA L40S scores 295,763, which is 7.5% lower than the MI300X. The NVIDIA RTX 6000 Ada Generation scores 287,237, which is 10.7% lower. This places the MI300X in a competitive band: it trails the highest-end NVIDIA parts by a single-digit percentage but leads the mid-range workstation cards by a similar margin.

Without a benchmark for the MI300A, the head-to-head analysis must infer from specifications. The MI300X’s FP32 throughput of 81.72 TFLOPS is 33% higher than the MI300A’s 61.29 TFLOPS. The texture rate of 2,553.6 GTexel/s is 33% higher than 1,915.2 GTexel/s. The shading unit count of 19,456 is 33% higher than 14,592. These ratios are consistent, suggesting the MI300X delivers roughly a third more raw compute across the board.

Memory bandwidth is identical at 5.32 TB/s, so memory-bound operations may see little difference between the two. The MI300X’s larger 192 GB capacity, however, allows it to hold larger working sets without spilling to slower storage. For workloads that fit in 128 GB, the MI300A could match the MI300X’s memory throughput, but the MI300X’s compute advantage would still apply.

Specification Differences

The two accelerators differ in exactly four recorded specification fields beyond the benchmark data. First, memory size: the MI300A has 128 GB of HBM3, while the MI300X has 192 GB. Second, shading units: the MI300A has 14,592, the MI300X has 19,456. Third, texture mapping units: the MI300A has 912, the MI300X has 1,216. Fourth, FP32 performance: the MI300A delivers 61.29 TFLOPS, the MI300X delivers 81.72 TFLOPS.

Additionally, the MI300X lists an FP16 performance figure of 81.72 TFLOPS (1:1), while the MI300A lists no FP16 value at all. This is a documented difference, though the absence of a figure for the MI300A may simply mean it was not recorded rather than that the capability is missing.

All other specification fields match exactly. Both use the Aqua Vanjaram chip, CDNA 3.0 architecture, 5 nm process, 153,000 million transistors, 1017 mm² die, and 150.4M per mm² transistor density. Both run at 1000 MHz base and 2100 MHz boost, with 1300 MHz memory and 5.2 Gbps effective. Both have an 8192-bit memory bus and 5.32 TB/s bandwidth. Both have 0 ROPs, 0 MPixel/s pixel rate, no ray tracing cores, no tensor cores, no display outputs, and no API support. Both are OAM Modules with no power connectors, a 750 W TDP, a 1150 W suggested PSU, and PCIe 5.0 x16. Both released on December 5, 2023, and both list Radeon Instinct as their predecessor.

FAQ

Q: Which accelerator has the higher recorded benchmark score?

A: The MI300X has a Geekbench OpenCL score of 317,994, placing it at the 100th percentile of all GPUs. The MI300A has no recorded benchmark score and sits at the 50th percentile with an average of zero.

Q: How does the MI300X compare to its nearest rivals?

A: The MI300X trails the NVIDIA H200 NVL by 5% (334,891) and the NVIDIA B200 by 8% (345,482). It leads the NVIDIA L40S by 7.5% (295,763) and the NVIDIA RTX 6000 Ada Generation by 10.7% (287,237).

Q: What is the memory capacity difference?

A: The MI300A carries 128 GB of HBM3, while the MI300X carries 192 GB. Both use an 8192-bit bus and deliver 5.32 TB/s bandwidth.

Q: Do the two accelerators share the same clock speeds?

A: Yes. Both have a base clock of 1000 MHz, a boost clock of 2100 MHz, and a memory clock of 1300 MHz with 5.2 Gbps effective.

Q: What is the FP32 performance gap?

A: The MI300X delivers 81.72 TFLOPS of FP32, which is 33% higher than the MI300A’s 61.29 TFLOPS.

Q: Are there any differences in power requirements?

A: No. Both accelerators have a 750 W TDP, use no power connectors, and recommend a 1150 W power supply. Both are OAM Modules with a PCIe 5.0 x16 interface.