AMD Instinct MI300 vs AMD Instinct MI308X Comparison

Head-to-Head Benchmarks

The database currently records no head-to-head benchmark results for the AMD Instinct MI300 and AMD Instinct MI308X. Both accelerators hold a 50th percentile position among all GPUs in the database, and their average benchmark scores are recorded as zero. This means no direct performance comparison can be derived from measured workloads at this time. The absence of scores does not reflect on either part's capability, rather it indicates that no standardized test data has been logged for these two compute accelerators.

Without recorded benchmark deltas, the analysis must rely on the specification differences that directly influence compute throughput. The MI308X delivers 81.72 TFLOPS of FP32 and FP16 (1:1) performance, while the MI300 delivers 47.87 TFLOPS in both precisions. That represents a 70.7% higher FP32 throughput for the MI308X based on the recorded figures. Texture rate follows a similar pattern: the MI308X reaches 2,553.6 GTexel/s versus 1,496.0 GTexel/s for the MI300, a 70.7% advantage as well. These are pure arithmetic comparisons derived from the database entries, not from executed benchmarks.

The pixel rate for both parts is recorded as 0 MPixel/s, which aligns with their compute-optimized design and lack of display outputs. Neither accelerator has any ROP output capability in the traditional graphics sense. The boost clock difference is substantial: the MI308X boosts to 2100 MHz while the MI300 boosts to 1700 MHz, a 400 MHz gap that contributes directly to the throughput differential. Base clocks are identical at 1000 MHz, and memory clocks match at 1300 MHz with 5.2 Gbps effective data rate.

Architecture Differences

Both accelerators share the same fundamental architecture: CDNA 3.0, built on the Aqua Vanjaram chip, fabricated by TSMC on a 5 nm process. The transistor count is identical at 153,000 million, and the die size matches at 1017 mm², yielding the same transistor density of 150.4M per mm². The memory type is HBM3 for both, with an identical 8192-bit bus width and 5.32 TB/s bandwidth. These commonalities indicate that the MI308X is a higher-configured variant of the same silicon rather than a new design.

The core configuration differs significantly. The MI300 uses 14,080 shading units and 880 texture mapping units. The MI308X increases this to 19,456 shading units and 1,216 texture mapping units. That is a 38.2% increase in shading units and a 38.2% increase in TMUs, directly scaling the compute resources. Neither part has ray tracing cores or tensor cores listed in the database, which is consistent with a pure compute accelerator design focused on FP32 and FP16 workloads.

Memory capacity is the other major architecture split. The MI300 carries 128 GB of HBM3, while the MI308X carries 192 GB, a 50% increase in capacity while maintaining the same bus width and bandwidth. This means the MI308X achieves its larger capacity without widening the memory interface, suggesting different memory stack configurations or higher density HBM3 stacks. Both parts use PCIe 5.0 x16 for host connectivity, and neither has display outputs. The API support is identical: DirectX, OpenGL, and Vulkan are all listed as N/A, reinforcing the compute-only positioning.

Where Each One Wins

The MI300 wins in power efficiency and physical integration flexibility. Its thermal design power is 600 W, which is 150 W lower than the MI308X's 750 W. The suggested power supply is 1000 W for the MI300 versus 1150 W for the MI308X. The MI300 uses two 8-pin power connectors, while the MI308X uses no power connectors because it is an OAM Module form factor. For systems that use standard PCIe power delivery, the MI300 is the compatible choice. The MI300 also has recorded physical dimensions of 267 mm length and 111 mm height, which allows for planning in chassis that accept standard-length accelerator cards.

The MI308X wins in raw compute throughput and memory capacity. Its 81.72 TFLOPS FP32 performance is 70.7% higher than the MI300's 47.87 TFLOPS. The FP16 throughput advantage is identical at 70.7%, which matters for workloads that operate in reduced precision. The texture rate advantage of 70.7% also favors the MI308X for any workload that stresses texture fetch operations, even though these are not traditional graphics parts. The 192 GB memory capacity versus 128 GB provides 50% more on-package storage, which directly benefits large model inference and training datasets that must reside in high-bandwidth memory.

The MI308X also boosts higher at 2100 MHz versus 1700 MHz, meaning its compute units operate at a faster clock when under load. The shading unit count advantage of 38.2% combines with the 23.5% higher boost clock to produce the overall throughput gap. The MI300's lower boost clock and fewer shading units cap its peak throughput, but its lower TDP makes it more suitable for dense multi-GPU enclosures where power and cooling budgets are constrained.

The MI300's release date is recorded as January 3, 2023, while the MI308X is dated December 5, 2023. Both share the same predecessor, Radeon Instinct, and neither has a recorded successor. The MI308X is the later release, which aligns with its higher specifications as a refined configuration of the same chip.

FAQ

Q: What is the FP32 performance difference between the MI300 and MI308X?

A: The MI308X delivers 81.72 TFLOPS, which is 70.7% higher than the MI300's 47.87 TFLOPS.

Q: How much memory does each accelerator have?

A: The MI300 has 128 GB of HBM3, while the MI308X has 192 GB of HBM3, a 50% capacity increase.

Q: Do these accelerators have any display outputs or graphics APIs?

A: Both have no display outputs, and DirectX, OpenGL, and Vulkan are all listed as N/A for both parts.

Q: What is the power consumption difference?

A: The MI300 has a TDP of 600 W with a suggested PSU of 1000 W, while the MI308X has a TDP of 750 W with a suggested PSU of 1150 W.

Q: Are the memory bandwidths the same?

A: Yes, both have 5.32 TB/s bandwidth over an 8192-bit bus with HBM3 at 1300 MHz.

Q: What form factor does each use?

A: The MI300 has a length of 267 mm and height of 111 mm with two 8-pin power connectors. The MI308X is an OAM Module with no power connectors listed.

Specification Differences

The following fields differ between the AMD Instinct MI300 and AMD Instinct MI308X:

• Boost clock: MI300 at 1700 MHz, MI308X at 2100 MHz
• Memory size: MI300 at 128 GB, MI308X at 192 GB
• Shading units: MI300 at 14,080, MI308X at 19,456
• Texture mapping units: MI300 at 880, MI308X at 1,216
• Texture rate: MI300 at 1,496.0 GTexel/s, MI308X at 2,553.6 GTexel/s
• FP32 performance: MI300 at 47.87 TFLOPS, MI308X at 81.72 TFLOPS
• FP16 performance: MI300 at 47.87 TFLOPS (1:1), MI308X at 81.72 TFLOPS (1:1)
• TDP: MI300 at 600 W, MI308X at 750 W
• Power connectors: MI300 uses 2x 8-pin, MI308X uses none
• Suggested PSU: MI300 at 1000 W, MI308X at 1150 W
• Slot width: MI300 has no recorded value, MI308X is OAM Module
• Dimensions: MI300 has 267 mm length and 111 mm height, MI308X has no recorded dimensions
• Release date: MI300 on January 3, 2023, MI308X on December 5, 2023

All other recorded specifications are identical: chip, architecture, process node, foundry, transistor count, die size, transistor density, base clock, memory clock, memory type, bus width, memory bandwidth, pixel rate, bus interface, display outputs, API support, predecessor, and production status. Both are listed at the 50th percentile among all GPUs in the database, and neither has recorded benchmark scores or nearest rivals.