MI355X vs RTX 3080

CDNA 4vsAmpereUpdated 36 days ago

MI355X emerges as the superior choice for most AI and computing tasks: its 2300 TFLOPS FP16/FP32 and 288 GB VRAM deliver performance unattainable by RTX 3080's 29.8 TFLOPS and 10-12 GB. Datacenter users prioritize this power despite higher costs and no current cloud offers.

Specifications Compared

SpecMI355XRTX-3080
TDP750W320W
VRAM288 GB10-12 GB
Memory TypeHBM3eGDDR6X
ArchitectureCDNA 4Ampere
Form FactorsOAMPCIe
InterconnectInfinity Fabric
FP8 Performance4,600 TFLOPS
FP16 Performance2,300 TFLOPS29.8 TFLOPS
FP32 Performance2300 TFLOPS29.8 TFLOPS
FP64 Performance72 TFLOPS
INT8 Performance4,600 TOPS
Memory Bandwidth8,000 GB/s760 GB/s

Performance Analysis

Compute capabilities differ dramatically: MI355X's 2300 TFLOPS FP16 supports training large neural networks at speeds 77 times higher than RTX 3080's 29.8 TFLOPS. FP32 parity at those rates aids scientific simulations on MI355X, while RTX 3080 struggles with complex models. FP8 performance of 4600 TFLOPS on MI355X accelerates inference for quantized models, unavailable on RTX 3080.

Memory bandwidth profoundly impacts workloads: MI355X's 8000 GB/s allows batch sizes for models over 288 GB VRAM, minimizing data movement overhead in training. RTX 3080's 760 GB/s restricts it to small batches on 10-12 GB VRAM, causing frequent swapping and slowdowns in inference.

Power demands reflect form factors: MI355X's 750W TDP suits OAM racks with Infinity Fabric scaling, while RTX 3080's 320W PCIe fits desktops. These specs translate to MI355X dominating large-scale AI, RTX 3080 viable for prototyping.

Live Cloud Pricing

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When to Choose the MI355X

Choose MI355X for large-scale LLM training or inference: 288 GB HBM3e VRAM loads entire models like those exceeding 100 billion parameters, avoiding multi-GPU sharding complexities. Its 8000 GB/s bandwidth and 2300 TFLOPS FP16 enable efficient handling of massive datasets in enterprise environments.

Infinity Fabric interconnect optimizes multi-node clusters, ideal for scientific computing with FP32 at 2300 TFLOPS.

When to Choose the RTX 3080

Opt for RTX 3080 in budget-constrained prototyping or fine-tuning small models: cloud pricing starts at $0.06 per hour, making it accessible for experimentation. 10-12 GB GDDR6X suffices for models under 10 GB, with 29.8 TFLOPS FP16 adequate for initial tests.

PCIe form factor and 320W TDP support single-user desktops or low-cost cloud instances across eight providers.

Use Cases

LLM Training
MI355X

MI355X's 288 GB HBM3e and 2300 TFLOPS FP16 handle massive models without sharding. RTX 3080's 10-12 GB VRAM limits scale.

LLM Inference
MI355X

4600 TFLOPS FP8 on MI355X enables high-throughput serving of large models. RTX 3080's 29.8 TFLOPS FP16 cannot compete.

Fine-tuning
Either

RTX 3080 suffices for small models at $0.06 per hour. MI355X excels for larger ones with 288 GB VRAM.

Stable Diffusion
RTX 3080

RTX 3080's 29.8 TFLOPS FP16 generates images quickly on 10 GB VRAM at low cost. MI355X overkill for consumer tasks.

Scientific Computing
MI355X

MI355X's 2300 TFLOPS FP32 and 8000 GB/s bandwidth accelerate simulations. RTX 3080's specs limit complex workloads.

Frequently Asked Questions

How much VRAM does MI355X have compared to RTX 3080?

MI355X features 288 GB HBM3e VRAM. RTX 3080 offers 10-12 GB GDDR6X. This enables MI355X to load models 24 times larger.

What is the FP16 performance difference?

MI355X achieves 2300 TFLOPS FP16. RTX 3080 reaches 29.8 TFLOPS. MI355X provides about 77 times more throughput.

Is RTX 3080 cheaper in the cloud?

RTX 3080 starts at $0.06 per hour, averaging $0.13 per hour across eight offers. MI355X has no live cloud pricing yet.

Which has higher memory bandwidth?

MI355X delivers 8000 GB/s. RTX 3080 provides 760 GB/s. MI355X supports over 10 times larger batch sizes.

What is the TDP for each GPU?

MI355X requires 750W TDP in OAM form factor. RTX 3080 uses 320W in PCIe. RTX 3080 suits lower-power setups.

Can RTX 3080 handle AI training?

RTX 3080 manages small-scale training with 29.8 TFLOPS FP16 on 10-12 GB VRAM. Large models require MI355X's 288 GB.

Which is cheaper to rent, the MI355X or the RTX 3080?

Cloud rental prices for both the MI355X and RTX 3080 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 MI355X have compared to the RTX 3080?

The MI355X has 288 GB of HBM3e memory. The RTX 3080 has 10 to 12 GB of GDDR6X memory.

Can I find MI355X and RTX 3080 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 MI355X and the RTX 3080?

The MI355X uses the CDNA 4 architecture (2025) while the RTX 3080 uses Ampere (2020). The MI355X delivers 77.2x the FP16 throughput and 10.5x the memory bandwidth of the RTX 3080.