topic Re:B580 eGPU Functionality and Rebar Support Issues in Graphics

B580 eGPU Functionality and Rebar Support Issues

NkArc — Fri, 24 Jan 2025 15:02:08 GMT

Hello Intel,

I received my B580 yesterday to get some additional performance for my current desktop; I managed to set up an External GPU rig with an 800W power supply that connects to my PC via Thunderbolt-4, which has a bandwidth around 40-Gbps. That said, there have been some performance issues with this card.

For starters, even though my motherboard and BIOS have Resizeable Bar and 4G enabled by default (I went ahead and double checked, and even reset my device just in case), the Intel Arc drivers weren't able to detect the Resizeable Bar, giving me the red "X Resizeable Bar" sign on the Intel Graphics Software. My GPU-Z stats also show that the GPU is not detecting the Rebar as well:

The performance of the card doesn't seem to be utilized to 10% of the card's capabilities. Running a game such as Tekken 8, I was only able to get around 45 fps on low with AI upscaling set to XeSS Performance while running this game at 1440p.

I'm not expecting the GPU to be fully utilized due to restrictions due to my bandwidth, but even then, the current performance is lower compared to my integrated graphics. Could it be possible that the current Intel graphics drivers do not support Rebar via Thunderbolt-4 at the moment?

Re:B580 eGPU Functionality and Rebar Support Issues

JedG_Intel — Mon, 27 Jan 2025 05:45:22 GMT

Hi NkArc,

Thank you for posting on Intel Community Forum.

I understand that you're experiencing functionality issues with B580 via Thunderbolt-4. Please share the information below for me to address this correctly.

1. Have you tried connecting the GPU directly without using Thunderbolt connection?

2. Are you using an All-In-One computer or laptop?

Additionally, to better understand your system's configuration, we kindly request that you download the Intel® System Support Utility for Windows* software. You can find the download link here: Intel® System Support Utility for Windows*

I look forward to your response.

Best regards,

Jed G.

Intel Customer Support Technician

Re:B580 eGPU Functionality and Rebar Support Issues

DhannielM_Intel — Fri, 31 Jan 2025 03:16:59 GMT

Hi NkArc,

I hope you're doing well. I'm following up to see if you've had a chance to review the questions I posted. Please let me know at your earliest convenience so we can determine the next steps to resolve this matter.

Best regards,

Dhanniel M.

Intel Customer Support Technician

Re:B580 eGPU Functionality and Rebar Support Issues

JedG_Intel — Wed, 05 Feb 2025 00:50:33 GMT

Hello NkArc,

I have not heard back from you so I will close this inquiry now. If you need further assistance, please submit a new question as this thread will no longer be monitored.

Best regards,

Jed G.

Intel Customer Support Technician

Re: B580 eGPU Functionality and Rebar Support Issues

Jacksofclubs — Thu, 04 Sep 2025 18:17:14 GMT

I believe he may have given up on the issue. Honestly, my 1070 Ti outperforms the B580 when used with my Thunderbolt 4 eGPU dock. After researching online, I found mixed reviews—some call the B580 terrible, while others praise it. I really want to get it working with my eGPU Thunderbolt Dock, so I can use my high-end system as my primary setup instead of relying on my server PC. I’ve been searching for software to enable Resizable BAR on the thunderbolt for intel GPUs, as it seems this feature is critical for compatibility.

I feel its been a while since the Arc B580, all the kinks should have work arounds. I am stuck with the card since i purchased while out of town and just found some free time to relax. Is there software or even hardware besides purchasing a brand new GPU i can do the get resizable bar to work through the thunderbolt 4? Maybe a thunderbolt accessory. i think there is a market that both intel and intel consumers could profit from this, or future opportunies.

Re: B580 eGPU Functionality and Rebar Support Issues

Aqualung — Mon, 19 Jan 2026 18:39:00 GMT

https://community.intel.com/t5/Intel-Arc-Discrete-Graphics/B580-limited-at-2-5GT-s-width-x1/m-p/1734042

Re: B580 eGPU Functionality and Rebar Support Issues

Xuhk12426 — Thu, 23 Apr 2026 04:57:06 GMT

i know its kind of late but it probably depends on the controller chip of your egpu dock usually buy intel's controller or like a asm2464pd, just don't go cheap