MI325X vs MI300X: What’s New, What Matters, and Why It Changes Your AI Stack

The AMD Instinct™ MI300X made waves when it launched with 192 GB of HBM3 memory per GPU, blazing-fast bandwidth around 5.3 TB/s, and real performance gains across AI training and inference. It quickly became a go-to accelerator for teams pushing large language models (LLMs), generative AI, and memory-heavy HPC workloads . Now, AMD is back with the MI325X, a new flagship accelerator in the Instinct lineup. It carries the same core CDNA3 architecture, but it’s upgraded where it counts: memory, bandwidth, and an inference-optimized design.

So, what’s new? What’s actually meaningful for AI engineers and technical decision-makers? And should you make the jump for your AI cloud infrastructure?

Let’s break it down.

MI325X vs MI300X: Spec-by-Spec Comparison

At first glance, the MI325X might seem like an incremental upgrade to the MI300X. After all, both are built on the CDNA 3 GPU architecture and deliver similar raw compute throughput. In fact, AMD confirms the peak math capabilities remain the same: up to ~1.3 PFLOPS of 16-bit (FP16/BF16) performance and ~2.6 PFLOPS of 8-bit (FP8/INT8) performance per chip, which is identical to the MI300X . However, the upgrades in memory capacity and speed are substantial, and they ripple through to real-world AI workloads.

• Memory Capacity: MI300X came with 192 GB of HBM3, whereas MI325X features 256 GB of the newer HBM3E memory on each GPU . That’s a 33% increase in VRAM per accelerator (and up to 50% more if fully using 36GB HBM3E stacks). More memory means larger models and datasets can be kept on a single GPU without offloading or partitioning. (For perspective, 8× MI325X GPUs in a server bring 2 TB of fast memory. This is enough to hold a 1-trillion-parameter model in memory, which wasn’t possible on previous-gen hardware .)
• Memory Bandwidth: Along with capacity, memory speed gets a bump. MI325X delivers 6 TB/s of memory bandwidth, up from ~5.3 TB/s on the MI300X . This ~13% jump in bandwidth comes purely from the HBM3E upgrade (the GPU cores run at similar clocks) . Higher bandwidth feeds the compute units more data and reduces bottlenecks in memory-intensive tasks.
• Architecture and Compute: Both accelerators use AMD’s 5nm CDNA3 architecture with 304 compute units (CUs) and support new lower-precision data types (FP8/INT8) with matrix engines. The MI325X is essentially the same compute silicon as MI300X, but AMD notes it as “CDNA 3 (tuned)” which is indicating minor optimizations and better firmware/driver tuning for the new memory. Importantly, ROCm support is first-class on both (AMD’s open software stack for GPUs), so existing MI300X-optimized software will run on MI325X with full compatibility. There’s no proprietary lock-in. You can use standard PyTorch, TensorFlow, and other frameworks on ROCm just as you would with CUDA, making integration into your AI stack straightforward.
• Power and Cooling: One change under the hood is a higher power envelope. The MI300X has a 750 W TDP (OAM module), whereas the MI325X is rated up to 1,000 W TDP . This reflects the additional memory and an “inferencing-first” tuning that keeps clocks high. In practice, that means MI325X runs hotter and demands robust cooling, a factor we’ll discuss later. AMD has improved power efficiency features (like fine-grained sparsity support) to offset this, but deploying MI325X at scale will require efficient cooling solutions to sustain peak performance .

Memory capacity and bandwidth leadership of MI325X vs a current competitor. MI325X packs 256 GB HBM3E and 6 TB/s bandwidth per GPU, leaping ahead of the previous generation and far surpassing other data center GPUs in memory headroom. More memory means larger models can be hosted on a single accelerator, and higher bandwidth keeps those massive models fed with data for training and inference.

In summary, spec-for-spec the MI325X’s headline improvements are memory size (256 GB vs 192 GB) and memory bandwidth (6 TB/s vs 5.3 TB/s) . The core math throughput remains similar to the MI300X , but that’s by design.  The MI300X was already extremely powerful, and the MI325X focuses on unleashing that power more effectively for large-scale AI. These spec upgrades might sound incremental on paper, but for many real-world AI workloads, they make a world of difference.

Let’s explore why.

What the Upgrades Mean for AI Workloads

Hardware specs only matter if they move the needle for your use case. The MI300X was a formidable GPU for AI; the MI325X takes its strengths further. Here’s what the differences mean in practice across training, fine-tuning, and inference scenarios for large models:

Bigger Models, Fewer GPUs (Training & Fine-Tuning Benefits)

One of the biggest pain points in training giant LLMs or even fine-tuning large models is memory. Models that don’t fit in a single GPU’s VRAM force you to shard weights across multiple GPUs, complicating your code and communication overhead. The MI325X’s 256 GB VRAM per card directly addresses this. It allows very large models (on the order of 70B+ parameters) to reside entirely on one GPU in half-precision. No sharding required. For example, a 70-billion parameter model (like Llama2-70B) easily fits in 16-bit precision with room to spare, and even 100B+ parameter models become feasible on a single MI325X. In contrast, with 192 GB on MI300X, some of these models might have been right at the limit or required splitting across two cards.

Why does this matter? It means less complexity and fewer GPUs needed to get the job done. A fine-tuning task that might have needed two MI300X GPUs to hold a model could potentially run on one MI325X. An 8-GPU MI325X server (2 TB total HBM3E) can handle models on the scale of 1 trillion parameters in memory,  something that previously might have required dozens of GPUs or a distributed cluster. Even for “smaller” models, having extra headroom means you can increase batch sizes or sequence lengths during training to improve convergence, without running out of memory. In short, more memory = more freedom to scale up model size and training throughput without scaling out your hardware as much.

For fine-tuning use cases, the memory boost is especially handy. Fine-tuning often involves loading a large pre-trained model (which now fits comfortably) and then updating it with relatively smaller datasets. With MI325X, a small team can fine-tune a 65B or 70B model on a single accelerator, simplifying the workflow drastically. This lowers the barrier to entry for organizations that want to adapt big models to their data without investing in multi-GPU clusters. The same CDNA3 architecture also means that any kernels or libraries optimized for MI300X (tensor operations, Transformers, etc.) perform equivalently on MI325X, but now you can run those on bigger models or larger batch sizes than before.

Faster Data Movement = Higher Throughput

Feeding data to 304 compute units at 2100 MHz is no small task. This is where that 6 TB/s memory bandwidth comes into play. The MI300X already had an impressive memory subsystem, but certain high-end workloads could still be memory-bound (for instance, large matrix multiplication with huge activations or models with very large context windows that read/write a lot of memory per inference). By cranking bandwidth ~13% higher, the MI325X keeps the GPU cores better fed and less idle, especially in large-batch or data-intensive operations .

In practical terms, higher bandwidth translates to higher throughput for many tasks. If you’re training with very large input sequences (say, >16k token contexts for LLMs or high-resolution images for multi-modal models), the faster HBM3E can deliver those tokens/pixels to the compute units faster, shaving some time off each training step. Similarly, for batched inference (running many queries in parallel on one GPU), memory bandwidth can be a limiting factor once the batch size grows and MI325X mitigates that.

Even for smaller batch, latency-critical inference, memory speed helps with things like faster loading of model layers and faster writing of output activations to memory. AMD has quoted that MI325X achieves around 20–30% lower latency on LLM inference compared to NVIDIA’s latest H200 in certain model tests (7B and 70B param models) , thanks in part to its memory and interconnect advantages. While MI300X was already competitive, the MI325X provides a cushion of extra bandwidth so you’re less likely to hit a memory throughput ceiling in your pipeline.

Another aspect is inter-GPU communication. MI325X GPUs, when used in multi-GPU setups, use AMD’s Infinity Fabric links (and the same 8-GPU baseboard design as MI300X). The faster memory indirectly means each GPU can handle more data, which puts pressure on interconnects, but AMD’s platform scales with a total of 48 TB/s aggregate memory bandwidth in an 8-GPU node . In essence, the whole system’s data movement capabilities are balanced to support high-throughput distributed training or inference. For large deployments, this helps avoid bottlenecks when scaling out to many GPUs.

Bottom line: throughput increases across the board. Whether it’s tokens processed per second in an LLM inference server, or images per second in a vision model training job, MI325X’s extra bandwidth and memory often translate to double-digit percentage improvements in those metrics over MI300X, assuming the workload was memory-bound or scaling-bound. And if your workload was purely compute-bound (i.e., fully utilizing the math units), then it will perform similarly on both, but in that case you likely care about the next point, efficiency.

Inference-First Design for AI Services

One notable angle in AMD’s strategy with the MI300X and MI325X is an “inference-first” design philosophy. These GPUs are clearly geared to excel at serving large AI models in production (while still being very capable for training). The massive memory is a big part of that… Enabling single-GPU inference for models that would otherwise require model parallelism. But beyond memory, the MI325X retains specialized hardware for lower-precision inference: support for FP8 and INT8 data types, and sparsity features that can double effective throughput for structured sparse models . This means you can deploy quantized models or leverage sparsity for much higher inference throughput without changing hardware. (Both MI300X and MI325X can leverage these features, but the extra memory in MI325X means you can cache larger lookup tables or more of the model in faster memory when doing things like retrieval-augmented generation.)

AMD’s claims against the competition underscore this inference focus. The MI325X’s FP8/INT8 peak is ~2.6 PFLOPS, about 30% higher than NVIDIA’s Hopper H200 (at ~2.0 PFLOPS) . In real-world terms, that gives MI325X an edge in maximum inference throughput. For example, generating responses with a giant transformer model or running an AI assistant serving thousands of users. If you’re deploying an AI service (chatbot, copilot, recommendation system, etc.), that can equate to serving more queries per second on the same hardware. Additionally, AMD has tuned the MI325X for better latency: as mentioned, early tests show notable latency reductions (20–30% lower) on example LLM inference tasks versus even the newest GPUs from competitors .

For real-time AI applications, think interactive chatbots, real-time decision engines, or streaming video analysis, those latency savings are crucial. The MI325X is able to deliver fast responses not just due to raw compute, but because it can keep the whole model in fast memory and avoid spilling data. And if your use case involves multi-modal AI (combining text, vision, etc.), the large memory means you can host multi-modal models (which tend to be huge) more easily, and the high bandwidth helps shuffle the different data types through without hiccups.

To be clear, the MI325X is not introducing brand-new tensor core technology beyond the MI300X, it’s an evolution that fine-tunes the balance for AI inference workloads. So while training speed (especially for smaller models) might not drastically change versus MI300X, the reliability and efficiency of deploying large models on MI325X is markedly better. In that sense, it “changes your AI stack” by enabling new deployment patterns: you can simplify inference serving architectures (serve one big model on one GPU instead of sharding across several), and you can confidently tackle models that were borderline impractical before.

MI325X on TensorWave’s AI Cloud Platform: Getting the Most Out of the Upgrade

Upgrading hardware is only part of the story. How you deploy that hardware makes a huge difference, especially when pushing the limits of power and scale. At TensorWave, we are bringing the MI325X into our AI cloud platform, fully production-ready and ROCm-optimized from day one. Our goal is to ensure that customers not only get access to MI325X accelerators, but also an environment that amplifies their benefits while smoothing over the rough edges that can come with any new chip. Here’s what that looks like:

• Liquid-Cooled, High-Density Clusters: Each MI325X OAM module can draw up to 1 kW of power, which can challenge traditional air-cooled setups. TensorWave deploys MI325Xs in liquid-cooled server clusters to keep temperatures low even under sustained full load. This means your training jobs won’t throttle and your inference services stay responsive, even as the GPUs turbo along at peak performance. Efficient cooling not only prevents thermal throttling but also extends hardware longevity and maintains better power efficiency. In practical terms, our liquid-cooled racks allow us to run 8× MI325X nodes (2 TB total VRAM per node) at full tilt, unlocking the promised 20+ PFLOPS of AI compute per node without hiccups.
• Large-Scale Deployment Expertise: We have built 8-GPU servers and multi-node clusters purpose-built for LLM training and large-scale inference. The Instinct MI325X platform supports eight GPUs per node connected via Infinity Fabric, and we network these nodes with ultra-high-bandwidth interconnects (200 Gb/s+ Ethernet/InfiniBand). This architecture is ideal for distributed training of giant models or serving thousands of concurrent model queries. Whether you need a single MI325X instance for fine-tuning or a 64-GPU cluster for a research project, our cloud can elastically scale to your needs. We’ve optimized the cluster topology to minimize communication overhead, so you get near-linear scaling on multi-GPU workloads. In short, we make scaling up or out with MI325X hardware as painless as possible.
• ROCm-Optimized Software Stack (No Lock-In): TensorWave’s AI cloud platform runs a fully open software stack based on AMD’s ROCm. You can bring your PyTorch, TensorFlow, JAX or ONNX models and run them with ROCm-optimized libraries that we maintain, no need to rewrite code. We’ve tuned kernel libraries and communication libraries (NCCL equivalent for ROCm, etc.) to get peak performance on MI300X and MI325X. Because ROCm is open source, you’re not locked into proprietary tooling or cloud-specific frameworks. This flexibility means you can develop on TensorWave and even run on your on-prem AMD systems or vice-versa with minimal friction. Our environment is set up to take full advantage of MI325X features (FP8 training support, mixed-precision routines, etc.) out of the box.
• End-to-End Visibility and Support: With new hardware, there can be a learning curve. TensorWave provides full-stack visibility into how your jobs are utilizing the MI325X GPUs, from hardware counters (SM utilization, memory throughput) to software metrics. Our engineers have deep experience with AMD Instinct GPUs (we’ve been running MI250s and MI300Xs at scale) and are on hand to help you squeeze every bit of performance for your specific model. We also ensure that your environment stays updated with the latest ROCm improvements and any future MI325X firmware optimizations. Essentially, we handle the “heavy lifting” of optimization and infrastructure, so you can focus on your model and application logic.

All of this means that when you run on TensorWave’s AI cloud platform, the MI325X isn’t just a spec sheet, it translates into real, tangible performance gains for your AI stack. Our liquid-cooled, large-memory GPU clusters let you do things like train a multi-hundred-billion parameter model without splitting across dozens of nodes, or deploy a conversational AI service on a single GPU that serves responses faster than ever. And you do so in an open environment with no vendor lock-in, giving you flexibility and control over your AI workflows.

Conclusion: A Clear Choice for the Future of AI Infrastructure

In the fast-paced world of AI hardware, the MI325X emerges as a clearly superior upgrade over the MI300X, particularly for those pushing the limits of model size and throughput. AMD has smartly targeted the bottlenecks that matter: by massively increasing memory capacity and boosting memory bandwidth, the MI325X opens new possibilities for training and deploying large AI models. It doesn’t reinvent the wheel.  Instead, it builds on a proven architecture and polishes it for real-world demands (especially inference and large-model workloads). This means you get an upgrade that is both high-impact and low-risk: your software stack carries over, but your performance and capabilities get a significant boost.

From an intellectual honesty standpoint, it’s worth noting that if your workloads are small or already well within the MI300X’s capabilities, you won’t suddenly see 10× speedups from MI325X. The raw compute (FP16/FP32 FLOPs) is unchanged , so pure compute-bound tasks run similarly. However, most modern AI workloads are not purely compute-bound, they hunger for memory and data movement. And that’s exactly where the MI325X shines. For training runs that struggled with memory limits, for fine-tuning sessions that needed awkward model parallel hacks, or for inference servers that craved more throughput, the MI325X can dramatically streamline your AI stack. Fewer GPUs to do the same job, simpler model distribution, higher single-GPU performance and it all leads to lower total cost of ownership and faster time-to-value for AI initiatives .

Importantly, by deploying MI325X in a thoughtfully designed environment (like TensorWave’s AI cloud platform), you can fully leverage its potential from day one. This combination of cutting-edge hardware and optimized infrastructure changes the game for what’s possible in the cloud. AI engineers and technical buyers evaluating their cloud infrastructure options should see the MI325X for what it is: not just a spec bump, but a strategic enabler for the next generation of AI applications. Whether you’re training sprawling new models or serving millions of queries, MI325X provides the headroom and performance to push further.

Should you make the jump? If your AI stack involves large-scale models or you’re aiming to keep pace with the rapid growth in model sizes and user demand, the MI325X isn’t just a nice-to-have, it’s quickly becoming a must-have. It changes your AI stack by allowing you to think bigger (models that were off-limits are now on the table) and run leaner (less hardware to achieve the same goal). In the ever-evolving landscape of AI accelerators, AMD’s MI325X stands out as a compelling, future-proof choice for those serious about performance and scalability in the cloud .

About TensorWave

TensorWave is the AMD AI cloud purpose-built for performance. Powered exclusively by AMD Instinct™ Series GPUs, we deliver high-bandwidth, memory-optimized infrastructure that scales with your most demanding models—training or inference.

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