R7725 caps RTX Pro 6000 Blackwell at 450W

Question

The NVIDIA RTX Pro 6000 Blackwell card supports running at 600W, sustaining higher performance.

The Dell R7725 rack server has been advertised by Dell as being capable of hosting this GPU (see https://www.youtube.com/watch?v=bye7OQLpkSg).

However, according to the R7725 manual (https://www.delltechnologies.com/asset/en-in/products/servers/technical-support/poweredge-r7725-technical-guide.pdf), it seems that the R7725 will cap the GPU at 450W, not allowing it to reach its 600W capacity.

Two questions:

1. Can confirm whether or not the RTX Pro 6000 Blackwell will be capped at 450W in the R7725?

2. If it is indeed capped at 450W, can you explain what is the expected impact on performance?

I am a user trying to decide what server to buy to host this GPU, and it is important for me to understand this before making a decision.

This question is a spin off from https://www.dell.com/community/en/conversations/rack-servers/dell-server-r770-and-the-new-rtx-pro-6000-blackwell-server-edition/689c6fbfafa0146bd1eb444b?commentId=689cde69c3c7331395906f35. Since that question is marked as "solved", I decided to open a new question.

DELL-Young E · Answer

Hello, and thank you for choosing Dell. We’re glad to have you as part of our community.

Regarding your inquiry, I’m afraid I can only refer to the information available in our official documentation, such as the user guide. For more tailored advice or configuration options, I recommend reaching out to our Sales team—they’ll be best equipped to assist you further.

I’m sorry I couldn’t provide a more specific solution this time, but we are here if you have any other questions.

Respectfully,

fr13 · Answer

Give that Dell has advertised R7725 as host for the RTX 6000 Blackwell, it would be nice to at least have some estimate of performance of this card at 450W compared to 600W.

DELL-Charles R · Answer

Hello,

You are correct that the GPU is capped at 450W.

You may like to review this Benchmarking and see if it answers some of your questions.

Some callout:

*Card peaked at 530W during this training run, never hit 600W

Key insight: Peak efficiency occurs at 300W, not at maximum power. For sustained workloads, 450W offers an excellent performance/thermal balance.

https://www.naveen.ing/writings/benchmarking-rtx-pro-6000/

fr13 · Answer

Thanks for the link. I would like to see more benchmarks like these.

In that link, for the LLM Inference Benchmarks one sees between 10% to 20% performance loss at 450W, compared to 600W. It's not huge, but it's significant enough that I think this point should be advertised and studied in some more detail, IMHO.

fr13 · Answer

What I would really like to see, is a performance benchmark for long workloads (e.g., an LLM model training for several days). If 600W is something one sees only at short bursts, then I'd expect in long running workloads capping at 450W will make no significant difference.

DELL-Young E · Answer

Hello, this falls outside the current scope of support, so unfortunately, I’m unable to assist directly. You're welcome to use any solution that best fits your needs. The limitations you're encountering are due to the server’s design, particularly around cooling and power capacity. If you're looking for higher performance, we do offer other server models with significantly more powerful GPU capabilities, though they come at a higher cost.

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R7725 caps RTX Pro 6000 Blackwell at 450W

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