A40 vs MI325X

AmperevsCDNA 3Updated 35 days ago

The MI325X emerges as the clear winner for most contemporary AI use cases, driven by 35 times higher FP16 performance at 1307 TFLOPS and 256 GB VRAM enabling unprecedented model scales. While the A40 remains viable at $0.24 per hour for accessible entry points, the MI325X defines future-proof dominance once available.

A40 from $0.08/hr

Specifications Compared

SpecA40MI325X
TDP300W750W
VRAM48 GB256 GB
CUDA Cores10,752
Memory TypeGDDR6HBM3e
ArchitectureAmpereCDNA 3
Form FactorsPCIeOAM
InterconnectNVLinkInfinity Fabric
Tensor Cores336
FP16 Performance37.4 TFLOPS1,307 TFLOPS
FP32 Performance37.4 TFLOPS1307 TFLOPS
FP64 Performance0.6 TFLOPS40.9 TFLOPS
INT8 Performance299 TOPS2,614 TOPS
Memory Bandwidth696 GB/s6,000 GB/s

Performance Analysis

Raw compute power sets the MI325X far ahead: its 1307 TFLOPS FP16 and FP32 dwarf the A40's 37.4 TFLOPS, translating to roughly 35 times faster matrix operations critical for deep learning training. This delta accelerates gradient computations and backpropagation, reducing training epochs for large language models from days to hours on equivalent node counts.

Memory bandwidth profoundly impacts real-world throughput: the MI325X's 6000 GB/s versus 696 GB/s allows 8.6 times larger data transfers per second, enabling massive batch sizes without stalling. For inference, this supports serving thousands of simultaneous requests at low latency, while the A40 bottlenecks on datasets over 40 GB. FP8 performance at 2614 TFLOPS on the MI325X further optimizes quantized inference, cutting precision needs for deployment-scale efficiency.

Power draw reflects these gains: the MI325X's 750W TDP demands robust cooling compared to the A40's 300W, influencing total cost of ownership in dense clusters.

Live Cloud Pricing

Real-time prices from 25+ providers. Updated every 60 seconds.

A40

ProviderGPU ModelVRAMHost SpecsRegionPriceStatusAction
TensorDock
TensorDock
NVIDIA RTX A4000
16GB VRAM
$0.08/GPU/hr
Available
Vast.ai
Vast.ai
8×NVIDIA RTX A4000
16GB VRAM
$0.15/GPU/hr
$1.17/hr total (8×)
Available
Hyperstack
Hyperstack
4×NVIDIA RTX A4000
16GB VRAM
$0.15/GPU/hr
$0.60/hr total (4×)
Available
Hyperstack
Hyperstack
2×NVIDIA RTX A4000
16GB VRAM
$0.15/GPU/hr
$0.30/hr total (2×)
Available
Hyperstack
Hyperstack
NVIDIA RTX A4000
16GB VRAM
$0.15/GPU/hr
Available

Compare real-time pricing across 25+ providers

When to Choose the A40

The A40 excels in cost-sensitive, immediately deployable scenarios with proven ecosystem support. Its pricing starts at $0.24 per hour across 23 live cloud offers, making it ideal for prototyping, smaller-scale inference, or visualization tasks fitting within 48 GB GDDR6. PCIe form factor ensures broad compatibility in existing data centers without NVLink or Infinity Fabric reconfiguration.

When to Choose the MI325X

Opt for the MI325X in memory-intensive frontier workloads like training or inferring on models over 100 billion parameters, leveraging 256 GB HBM3e to avoid sharding. Superior 6000 GB/s bandwidth and 1307 TFLOPS FP16 sustain peak throughput for hyperscale AI, despite 750W TDP and OAM form factor requiring specialized infrastructure.

Use Cases

LLM Training
MI325X

MI325X's 1307 TFLOPS FP16 and 256 GB VRAM handle massive datasets and parameters without multi-GPU complexity, far surpassing A40's 37.4 TFLOPS and 48 GB limits.

LLM Inference
MI325X

6000 GB/s bandwidth on MI325X supports enormous batch sizes for high-concurrency serving, with 2614 TFLOPS FP8 optimizing quantized models beyond A40's 696 GB/s capacity.

Fine-tuning
MI325X

MI325X accelerates iterations with 1307 TFLOPS FP32, fitting full models in 256 GB to minimize overhead, unlike A40's constraints at 48 GB.

Stable Diffusion
Either

A40's 48 GB suffices for standard resolutions at 37.4 TFLOPS, but MI325X's 256 GB enables ultra-high-res or batch generations with 6000 GB/s throughput.

Scientific Computing
MI325X

MI325X's 1307 TFLOPS FP32 and vast memory excel in simulations requiring terabyte-scale data, outpacing A40's 37.4 TFLOPS for complex HPC workloads.

Frequently Asked Questions

Which GPU has more VRAM: A40 or MI325X?

The MI325X offers 256 GB HBM3e VRAM, compared to the A40's 48 GB GDDR6. This makes the MI325X suitable for models exceeding 100 billion parameters.

How does memory bandwidth compare between A40 and MI325X?

MI325X provides 6000 GB/s, over 8 times the A40's 696 GB/s. Higher bandwidth reduces bottlenecks in large-batch training and inference.

What is the FP16 performance of these GPUs?

A40 delivers 37.4 TFLOPS FP16, while MI325X reaches 1307 TFLOPS. This gap accelerates AI workloads by approximately 35 times on MI325X.

Is the A40 cheaper in the cloud than MI325X?

A40 starts at $0.24 per hour across 23 offers, averaging $1.26 per hour. MI325X has no live offers currently.

What are the TDPs for A40 and MI325X?

A40 consumes 300W TDP, versus MI325X's 750W. Lower TDP on A40 eases cooling in standard racks.

Which architecture is newer?

MI325X uses CDNA 3 from 2024, succeeding Ampere 2020 on A40. Newer design incorporates FP8 at 2614 TFLOPS.

Which is cheaper to rent, the A40 or the MI325X?

Cloud rental prices for both the A40 and MI325X vary by provider, configuration, and availability. This page shows live pricing from 25+ providers updated every 60 seconds. Scroll to the Live Cloud Pricing section to compare current rates.

How much VRAM does the A40 have compared to the MI325X?

The A40 has 48 GB of GDDR6 memory. The MI325X has 256 GB of HBM3e memory.

Can I find A40 and MI325X GPUs available to rent right now?

Yes. This page shows real-time availability across 25+ cloud GPU providers. The Live Cloud Pricing section displays only in-stock offers with current pricing.

What is the main difference between the A40 and the MI325X?

The A40 uses the Ampere architecture (2020) while the MI325X uses CDNA 3 (2024). The MI325X delivers 34.9x the FP16 throughput and 8.6x the memory bandwidth of the A40.

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