MI355X vs RTX 3090 Ti

CDNA 4vsAmpereUpdated 35 days ago

The MI355X dominates for AI and HPC use cases: its 288 GB VRAM, 8000 GB/s bandwidth, and 2300 TFLOPS FP16/FP32 crush the RTX 3090 Ti's 24 GB, 936 GB/s, and 35.6 TFLOPS, enabling production-scale training and inference despite higher 750W TDP and absent pricing.

RTX 3090 Ti from $0.20/hr

Specifications Compared

SpecMI355XRTX-3090
TDP750W350W
VRAM288 GB24 GB
Memory TypeHBM3eGDDR6X
ArchitectureCDNA 4Ampere
Form FactorsOAMPCIe
InterconnectInfinity FabricNVLink
FP8 Performance4,600 TFLOPS
FP16 Performance2,300 TFLOPS35.6 TFLOPS
FP32 Performance2300 TFLOPS35.6 TFLOPS
FP64 Performance72 TFLOPS
INT8 Performance4,600 TOPS
Memory Bandwidth8,000 GB/s936 GB/s

Performance Analysis

Compute throughput sets these GPUs apart: the MI355X reaches 2300 TFLOPS in FP16 and FP32, accelerating LLM training epochs by orders of magnitude over the RTX 3090 Ti's 35.6 TFLOPS, which handles only modest model sizes. In inference, the MI355X's 4600 TFLOPS FP8 performance enables high-concurrency serving of models exceeding 100 billion parameters, while the RTX 3090 Ti limits requests to smaller batches.

Memory capacity and speed dictate real-world viability: 288 GB HBM3e at 8000 GB/s on the MI355X supports enormous batch sizes in training without gradient checkpointing, slashing memory bottlenecks common on the RTX 3090 Ti's 24 GB GDDR6X at 936 GB/s. Power efficiency follows suit with the MI355X at 750W TDP versus 350W, but yields far higher flops per watt in precision tasks.

Interconnects differ too: Infinity Fabric on the MI355X scales multi-GPU clusters seamlessly, outperforming NVLink on the PCIe-based RTX 3090 Ti for distributed workloads.

Live Cloud Pricing

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

RTX 3090 Ti

ProviderGPU ModelVRAMHost SpecsRegionPriceStatusAction
TensorDock
TensorDock
NVIDIA GeForce RTX 3090
24GB VRAM
$0.20/GPU/hr
Available
TensorDock
TensorDock
NVIDIA GeForce RTX 3090
24GB VRAM
$0.21/GPU/hr
Available
Vast.ai
Vast.ai
4×NVIDIA GeForce RTX 3090
24GB VRAM
$0.25/GPU/hr
$1.01/hr total (4×)
Available
Vast.ai
Vast.ai
4×NVIDIA GeForce RTX 3090
24GB VRAM
$0.27/GPU/hr
$1.07/hr total (4×)
Available
LeaderGPU
LeaderGPU
8×NVIDIA GeForce RTX 3090
24GB VRAM
$0.29/GPU/hr
$2.29/hr total (8×)
Available

Compare real-time pricing across 25+ providers

When to Choose the MI355X

Opt for the MI355X in large-scale LLM training or inference where 288 GB VRAM loads full models without sharding, and 8000 GB/s bandwidth sustains peak 2300 TFLOPS FP16 throughput. It excels in scientific computing simulations demanding sustained FP32 at 2300 TFLOPS or FP8 inference at 4600 TFLOPS across OAM-deployed clusters.

When to Choose the RTX 3090 Ti

Choose the RTX 3090 Ti for budget prototyping, Stable Diffusion generation, or fine-tuning small models under 20 GB, available from $0.10 per hour. Its 24 GB GDDR6X and 936 GB/s bandwidth suffice for consumer AI tasks or gaming at 350W TDP in PCIe slots, avoiding datacenter setup complexities.

Use Cases

LLM Training
MI355X

The MI355X's 288 GB HBM3e VRAM and 2300 TFLOPS FP16 handle massive models without sharding, unlike the RTX 3090 Ti's 24 GB limit.

LLM Inference
MI355X

4600 TFLOPS FP8 and 8000 GB/s bandwidth on the MI355X support high-throughput serving of large LLMs, far beyond the RTX 3090 Ti's 35.6 TFLOPS.

Fine-tuning
Either

RTX 3090 Ti suffices for models under 24 GB at $0.10 per hour; MI355X accelerates larger ones with 288 GB VRAM.

Stable Diffusion
RTX 3090 Ti

RTX 3090 Ti's 24 GB GDDR6X and 936 GB/s optimize image generation workflows cost-effectively from $0.10 per hour.

Scientific Computing
MI355X

MI355X delivers 2300 TFLOPS FP32 for simulations, with Infinity Fabric scaling clusters better than RTX 3090 Ti's NVLink.

Frequently Asked Questions

Which has more VRAM: MI355X or RTX 3090 Ti?

The MI355X provides 288 GB HBM3e VRAM, twelve times the RTX 3090 Ti's 24 GB GDDR6X. This enables loading massive AI models without multi-GPU splitting.

How do FP16 performance numbers compare?

MI355X achieves 2300 TFLOPS FP16, over 64 times the RTX 3090 Ti's 35.6 TFLOPS. This gap accelerates deep learning training significantly.

What is the memory bandwidth difference?

MI355X offers 8000 GB/s with HBM3e, versus RTX 3090 Ti's 936 GB/s GDDR6X. Higher bandwidth reduces bottlenecks in large batch training.

Is there cloud pricing for MI355X?

No live offers exist for MI355X currently. RTX 3090 Ti starts at $0.10 per hour, averaging $0.25 per hour across five providers.

Which GPU has higher TDP?

MI355X draws 750W TDP, more than double the RTX 3090 Ti's 350W. It delivers superior performance density for datacenter use.

Can RTX 3090 Ti handle LLM inference?

RTX 3090 Ti manages inference for models under 24 GB at 35.6 TFLOPS FP16. Larger models require MI355X's 288 GB and 4600 TFLOPS FP8.

Which is cheaper to rent, the MI355X or the RTX 3090?

Cloud rental prices for both the MI355X and RTX 3090 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 3090?

The MI355X has 288 GB of HBM3e memory. The RTX 3090 has 24 GB of GDDR6X memory.

Can I find MI355X and RTX 3090 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 3090?

The MI355X uses the CDNA 4 architecture (2025) while the RTX 3090 uses Ampere (2020). The MI355X delivers 64.6x the FP16 throughput and 8.5x the memory bandwidth of the RTX 3090.

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