AMD Instinct MI308X vs AMD Radeon Instinct MI300X Comparison

FAQ

Q: What are the core specifications of the AMD Instinct MI308X and the AMD Radeon Instinct MI300X?

A: Both accelerators are built on the same fundamental silicon. They use the Aqua Vanjaram chip, are manufactured on TSMC's 5 nm process, and each contains 153,000 million transistors on a 1017 mm² die. Both feature 19,456 shading units, 1,216 texture mapping units, and are configured with 192 GB of HBM3 memory on an 8192-bit bus.

Q: How do the memory clocks and bandwidth compare between the two cards?

A: The MI308X operates its memory at 1300 MHz with 5.2 Gbps effective data rate, yielding 5.32 TB/s of bandwidth. The MI300X runs its memory at 2525 MHz with 10.1 Gbps effective, producing 10.3 TB/s. The MI300X therefore provides nearly double the memory bandwidth of the MI308X.

Q: Are there any differences in the FP32 compute performance?

A: No. Both cards deliver identical FP32 performance at 81.72 TFLOPS. The texture fill rate is also the same at 2,553.6 GTexel/s, and both have a pixel rate of 0 MPixel/s since they lack ROPs.

Q: What is the difference in FP16 compute capability?

A: The difference is substantial. The MI308X provides 81.72 TFLOPS FP16 with a 1:1 ratio relative to FP32. The MI300X provides 653.7 TFLOPS FP16, but at an 8:1 ratio. The MI300X offers 8 times the raw FP16 throughput, albeit with a different ratio configuration.

Q: Do these cards have any display outputs or standard API support?

A: Both are compute-only accelerators with no display outputs. The MI308X lists DirectX, OpenGL, and Vulkan support as N/A. The MI300X does not list any API support in the database, also indicating no graphics API functionality.

Q: What are the power requirements for these accelerators?

A: Both cards have a TDP of 750 W and a suggested power supply rating of 1150 W. They use OAM Module slot width and do not use standard power connectors. Both interface via PCIe 5.0 x16.

Architecture Differences

The AMD Instinct MI308X and AMD Radeon Instinct MI300X share the same foundational architecture. Both are built on CDNA 3.0, use the Aqua Vanjaram chip, and are 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. The transistor density of 150.4M per mm² is also the same for both.

The core compute configuration is identical. Each card has 19,456 shading units and 1,216 TMUs. Neither card has ROPs, RT cores, or dedicated tensor cores listed. The pixel rate is 0 MPixel/s for both, and the texture rate is 2,553.6 GTexel/s. The base clock is 1000 MHz and the boost clock is 2100 MHz for both accelerators.

The most significant architectural divergence appears in the memory clock domain. The MI308X runs its HBM3 memory at 1300 MHz with an effective data rate of 5.2 Gbps. The MI300X runs the same memory type at 2525 MHz with an effective rate of 10.1 Gbps. This clock difference directly translates into a bandwidth difference, with the MI300X achieving 10.3 TB/s versus 5.32 TB/s for the MI308X.

The FP16 execution path also differs notably. The MI308X implements FP16 at a 1:1 ratio with FP32, meaning both datatypes run at the same throughput of 81.72 TFLOPS. The MI300X implements FP16 at an 8:1 ratio, which allows it to reach 653.7 TFLOPS. This indicates a different approach to packed math throughput, where the MI300X is optimized for higher FP16 throughput while the MI308X maintains a symmetric FP32/FP16 configuration.

The API support differs in the database entries. The MI308X explicitly lists DirectX, OpenGL, and Vulkan as N/A. The MI300X does not provide any API data, which suggests both are designed exclusively for compute workloads without graphics API compatibility.

Both cards share the same power architecture. The TDP is 750 W, the suggested PSU is 1150 W, and both use OAM Module slot width with no power connectors. The bus interface is PCIe 5.0 x16 for both. Neither card has display outputs.

The release date is the same for both: December 5, 2023. The predecessor differs slightly in naming, with the MI308X listing Radeon Instinct and the MI300X listing FirePro Data Center.

Head-to-Head Benchmarks

The database contains no recorded head-to-head benchmark results for these two accelerators. Both cards have an average benchmark score of 0 and a percentile ranking of 50 among all GPUs. There are no wins recorded for either card in the head-to-head comparison data.

The absence of benchmark scores means the comparison must rely entirely on the specification data. The FP32 performance is identical at 81.72 TFLOPS, so any workload that depends on standard FP32 math will see no measurable difference between the two cards. The texture rate is also identical at 2,553.6 GTexel/s, indicating similar performance in texture-bound operations.

The memory bandwidth difference is the clearest differentiator. The MI300X delivers 10.3 TB/s, which is approximately 94% higher than the 5.32 TB/s of the MI308X. This is a substantial advantage for memory-intensive workloads such as large language model inference, where bandwidth often limits throughput.

The FP16 performance gap is even more pronounced. The MI300X provides 653.7 TFLOPS, which is exactly 8 times the 81.72 TFLOPS of the MI308X. For workloads that exploit FP16 packed math, such as certain AI training operations, the MI300X has a clear theoretical advantage.

The MI308X does not win any specification category outright. It matches the MI300X in FP32, texture rate, memory capacity, bus width, clock speeds, TDP, and form factor. The only meaningful difference is that the MI308X uses a 1:1 FP16 ratio, which may be preferable for workloads that require symmetric precision handling, but it does not produce a higher throughput number.

Specification Differences

The following fields differ between the AMD Instinct MI308X and the AMD Radeon Instinct MI300X:

Memory Clock: The MI308X has a memory clock of 1300 MHz with 5.2 Gbps effective. The MI300X has a memory clock of 2525 MHz with 10.1 Gbps effective.

Memory Bandwidth: The MI308X achieves 5.32 TB/s. The MI300X achieves 10.3 TB/s.

FP16 Performance: The MI308X delivers 81.72 TFLOPS with a 1:1 FP32 ratio. The MI300X delivers 653.7 TFLOPS with an 8:1 FP32 ratio.

API Support: The MI308X lists DirectX, OpenGL, and Vulkan as N/A. The MI300X has no API data listed.

Generation Naming: The MI308X is listed under the Instinct (MIx) generation. The MI300X is listed under the Radeon Instinct (MIx) generation.

Predecessor: The MI308X lists Radeon Instinct as its predecessor. The MI300X lists FirePro Data Center.

All other specifications are identical. Both use the Aqua Vanjaram chip, CDNA 3.0 architecture, 5 nm process, 153,000 million transistors, 1017 mm² die size, 150.4M per mm² transistor density, 1000 MHz base clock, 2100 MHz boost clock, 192 GB HBM3 memory, 8192-bit bus width, 19,456 shading units, 1,216 TMUs, 0 ROPs, 0 MPixel/s pixel rate, 2,553.6 GTexel/s texture rate, 81.72 TFLOPS FP32, 750 W TDP, OAM Module slot width, no power connectors, 1150 W suggested PSU, PCIe 5.0 x16 bus interface, no display outputs, and a release date of December 5, 2023. Neither card has a launch MSRP recorded in the database.

Where Each One Wins

AMD Radeon Instinct MI300X: The MI300X is the clear winner in memory bandwidth. With 10.3 TB/s versus 5.32 TB/s, it offers approximately 94% more bandwidth. This makes it the stronger choice for workloads that are bandwidth-limited, such as large-scale AI inference, dense matrix operations that rely on memory access patterns, and any application that processes data sets larger than the on-chip cache. The FP16 advantage is also decisive. At 653.7 TFLOPS, the MI300X provides exactly 8 times the FP16 throughput of the MI308X. This matters for training and inference workloads that use mixed-precision arithmetic, where the 8:1 ratio allows substantially higher throughput. The memory clock difference also favors the MI300X, with 2525 MHz versus 1300 MHz, which may translate into lower latency for certain access patterns.

AMD Instinct MI308X: The MI308X does not have a single specification category where it outperforms the MI300X. It matches the MI300X in FP32 performance at 81.72 TFLOPS, texture rate at 2,553.6 GTexel/s, memory capacity at 192 GB, and bus width at 8192 bits. The 1:1 FP16 ratio is a configurational difference rather than a performance advantage. For workloads that require symmetric FP32 and FP16 throughput, the MI308X provides that symmetry, whereas the MI300X does not. This could matter for certain numerical algorithms that alternate between FP32 and FP16 operations and benefit from consistent throughput across both datatypes. However, the raw throughput numbers do not give the MI308X a win in any measured category.

Workload Split: Based on the recorded data, the MI300X is the preferred accelerator for memory-bound and FP16-heavy workloads. The 10.3 TB/s bandwidth and 653.7 TFLOPS FP16 performance are the defining advantages. The MI308X is the appropriate choice when the 1:1 FP16 ratio is a requirement, or when the workload is purely FP32-bound, in which case both cards perform identically. The identical FP32 performance means that any FP32-only workload will show no difference between the two cards. The MI300X's higher memory bandwidth does not degrade FP32 performance, so it remains the stronger all-around choice for most compute scenarios. The database records no benchmark wins for either card, so these conclusions are drawn entirely from the specification differences.