# Can Ampere Altra Max + ALTRAD8UD-1L2T support Direct PCIe peer-to-peer DMA from BlueField-3 NIC → GPU memory?

**URL:** https://community.amperecomputing.com/t/can-ampere-altra-max-altrad8ud-1l2t-support-direct-pcie-peer-to-peer-dma-from-bluefield-3-nic-gpu-memory/3280
**Category:** General Discussion
**Tags:** ampere
**Created:** [December 15, 2025, 2:04am UTC](https://community.amperecomputing.com/t/can-ampere-altra-max-altrad8ud-1l2t-support-direct-pcie-peer-to-peer-dma-from-bluefield-3-nic-gpu-memory/3280 "2025-12-15T02:04:46Z")
**Posts on this page:** 2
**Page:** 1

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### Author: ![dping](https://avatars.discourse-cdn.com/v4/letter/d/5f9b8f/32.png) [@dping](https://community.amperecomputing.com/u/dping)
#### Post date: [December 15, 2025, 2:04am UTC](https://community.amperecomputing.com/t/can-ampere-altra-max-altrad8ud-1l2t-support-direct-pcie-peer-to-peer-dma-from-bluefield-3-nic-gpu-memory/3280/1 "2025-12-15T02:04:46Z")

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Can Ampere Altra Max + ALTRAD8UD-1L2T support Direct PCIe peer-to-peer DMA from BlueField-3 NIC → GPU memory with below setup?

Setup **CPU:** Ampere Altra M128-26 (ARM64)

- **Motherboard:** ASRock Rack ALTRAD8UD-1L2T

- **GPU:** NVIDIA RTX 6000 Ada

- **NIC:** NVIDIA BlueField-3

- **CPU:** Ampere Altra M128-26 (ARM64)

Looks like Ampere Altra uses **multiple isolated PCIe host bridges and** ARM **SMMU enforces strict DMA isolation**

Also **No routing of peer transactions** between host bridges. So GPUDirect RDMA **cannot cross those boundaries.**

**Is that our understand correct? Is there any way to make it work?**

Thank you very much

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### Author: ![quocbao](https://yyz1.discourse-cdn.com/flex027/user_avatar/community.amperecomputing.com/quocbao/32/1035_2.png) [@quocbao](https://community.amperecomputing.com/u/quocbao)
#### Post date: [December 16, 2025, 11:11am UTC](https://community.amperecomputing.com/t/can-ampere-altra-max-altrad8ud-1l2t-support-direct-pcie-peer-to-peer-dma-from-bluefield-3-nic-gpu-memory/3280/2 "2025-12-16T11:11:52Z")

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Ampere CPUs are not designed for your use case 😂

If you want “PCIe peer-to-peer”, go looking for servers having the bridge in the red circle.

 ![CleanShot 2025-12-16 at 18.13.08@2x](https://canada1.discourse-cdn.com/flex027/uploads/amperedevelopers/original/2X/2/2fd58b1f4eea003e40033905746060daed22358c.jpeg)

If you want true high-speed peer-to-peer GPU bandwidth, go looking for SXM GPU.