RTX 4090 vs RTX 5090 for LLMs: is the upgrade worth it?

RTX 4090 vs RTX 5090 for LLMs: 24GB or 32GB?

The RTX 4090 has 24GB; the RTX 5090 has 32GB. The clearest capacity case for upgrading is a workload that exceeds the usable memory of the 4090 but fits on the 5090. Include model weights, context cache, concurrent requests and working buffers.

If both cards keep the entire workload on the GPU, the extra capacity alone does not tell you the speed difference. If the workload exceeds 32GB too, compare a smaller artifact or a higher-capacity setup before buying.

How much faster is the 5090 for AI?

We do not have a matched test establishing a tokens-per-second ratio. Require the same model file, quantization, runtime version, context length and concurrency when comparing results. Record prompt-processing speed, time to first token, generation speed and peak memory separately.

Check whether either result uses CPU offload. A fully GPU-resident run and a partially offloaded run answer a different question from a same-workload GPU speed comparison. Confirm that Blackwell is supported by the application and extensions you use.

Why is a 4090 listing more expensive than a 5090?

A particular listing can cost more because the comparison mixes board variants, condition, warranty, shipping or seller pricing. An asking price is not a completed sale. These are possibilities to investigate, not a finding that one factor explains the current market.

Compare like-for-like checkout totals and inspect the dated sample medians above. Exclude accessories, damaged cards and misleading model names. A single expensive 4090 does not establish that 4090s generally cost more, or that they perform better.

Should you trade a 4090 for a 5090?

Calculate net upgrade cost as the 5090 checkout total plus required system upgrades, minus the net proceeds from selling your 4090. Deduct selling fees and shipping from those proceeds. For a trade-in, use the actual offer and account for any conditions.

Then identify what the expense buys: a workload that fits without offloading, a measured time saving, or a required supported feature. If your current setup already meets the target, keeping it avoids the replacement expense. Follow the exact board manufacturer’s connector, clearance and power-supply guidance.

Sources and review

• NVIDIA RTX 4090 specifications
• NVIDIA RTX 5090 specifications
• Ollama hardware support by operating system
• Ollama context and memory requirements

FAQ

Is the RTX 5090 better than the RTX 4090 for LLMs?

The 5090 provides 32GB versus 24GB, which can help a workload that no longer fits on the 4090. For workloads that fit on both, compare matched inference results and net upgrade cost rather than assuming a fixed speed advantage.

How much faster is the RTX 5090 for AI inference?

We have not measured a universal ratio. Model, quantization, context, runtime and offloading affect the result. Compare prompt processing and token generation separately under the same conditions.

Why is the RTX 4090 more expensive than the RTX 5090?

That can be true of individual listings without being true of the market. Check condition, board variant, warranty, shipping and seller pricing. Use comparable current listings; an inflated asking price is not proof of higher value.

Should I trade my RTX 4090 for an RTX 5090?

Upgrade when the extra memory or a demonstrated workload improvement is worth the net cost after selling or trading your 4090. Include transaction costs and any required host upgrades.

Can a 32GB RTX 5090 run every 70B model?

No. Fit depends on the exact artifact and quantization plus context cache and working memory. Parameter count and installed VRAM alone are insufficient.