eGPU Selection

[Subhydro]

I am currently running three monitors off my laptop using an HP thunderbolt dock, but I am having dropouts and slowdowns when handling large spatial data sets. I work in 1080p and do not need gaming refresh rates. i just need to be able to manipulate (move around, zoom in and out of,  examine) spatial data sets of sizes around 100 - 200 gbs.

I would like to get an eGPU enclosure and an external NVIDIA graphics  card to see if this improves the situation, and I'm hoping the community can answer three questions:

1) Does my Spectre laptop support eGPU use through it's thunderbolt ports?
2) What type of enclosure specs should I be looking for to be compatible with my power and data needs?
3) What is the maximum performance external card I can use over thunderbolt before hitting thunderbolt bandwidth bottlenecks?

[Max3Aj · Accepted solution]

@Subhydro, Welcome to HP Support Community. 

Thank you for posting your query, I will be glad to help you. 
Great setup and solid questions—especially for someone working with large spatial datasets. Let’s walk through each one:

1. Does your HP Spectre x360 16-aa0000 support eGPU over Thunderbolt?

Yes, it does. Your model supports Thunderbolt 4, which is backward compatible with eGPU enclosures using Thunderbolt 3/4. Thunderbolt 4 provides 40 Gbps bandwidth and supports external GPUs. While HP doesn’t officially advertise eGPU support, many community users have successfully used eGPUs with HP Spectre laptops.Important Note: Ensure that Thunderbolt is set to “Always Connected” and “No Security” or “User Authorization” in the BIOS if you run into connectivity issues.
 

2. What type of enclosure specs should I be looking for?

Look for these minimum specs in a Thunderbolt eGPU enclosure:

Thunderbolt TB3 or TB4 (TB4 preferred if available)
PSU Wattage At least 650W (for higher-end GPUs)
GPU Size Support Full-length, double/triple-slot cards 
 

3. What is the maximum GPU performance over Thunderbolt before bottlenecks?

Thunderbolt 3/4 offers PCIe 3.0 x4 bandwidth, which is about half the bandwidth of PCIe 3.0 x16 that GPUs use internally. This means:

• High-end GPUs (e.g., RTX 4090/4080) will be bandwidth-limited, especially in gaming or data transfer-heavy tasks.
• For non-gaming workloads (like GIS, spatial analytics, 3D rendering), the bottleneck is less critical.

Using NVIDIA’s Studio drivers (instead of Game Ready drivers) might help with stability and performance in apps like ArcGIS, QGIS, or other CAD tools.

Bonus Tips:

• Avoid USB-C docks for GPU output—always connect monitors directly to the eGPU to take advantage of the external GPU’s power.
• Use DisplayPort or HDMI from the eGPU, not Thunderbolt pass-through.
• If using heavy RAM on spatial data, ensure your laptop has maxed-out RAM (32GB preferred).

I hope this helps. 

Take care and have a good day. 

Please click “Accepted Solution” if you feel my post solved your issue, it will help others find the solution. Select "Yes" on the bottom left to say “Thanks” for helping! 

Max3Aj

HP Support 

[Subhydro]

Hey Max3Aj,

Thank you for your response, that is a great start. A couple of follow ups if you would be so kind:

1) The two enclosures I'm looking at are both 750w. Sonnettech 750ex (my preferred) supports 85w TB power  and the Razer Core X 100w TB power. The power adaptor that came with my laptop is the 140w variety to support the discrete Nvidia GPU I have onboard my laptop. 

Will either of these eGPU enclosures charge my laptop while in use or will I have to connect the power supply to the second TB port on my laptop? 

2) If I have to connect the power supply do I need to disable any power coming from the eGPU so that I don't have two sources of charging hot the laptop concurrently?

3) I am looking at previous generation GPU cards that are still available and are far more cost efficient. Are there some numbers I can look at in the card specs to match with the 40gbs TB bottleneck?  For example the Nvidia RTX A4000 Graphics Card is now available at half RRP but it is still a pricey card. Is this too much for connecting over TB4 and how can I determine this from the specs?

4) When connected to my eGPU, is it possible to have the laptop's onboard Nvidia GPU run the laptop screen for comms tasks(teams, slack, outlook etc), and hand any other screens (up to 4 x 27" or 2 x 49") off to the eGPU for the spatial data work and other graphics intense applications?

Thank you in advance

[Max3Aj]

@Subhydro, Thank you for your response. 
You're very welcome! Those are excellent follow-up questions—let’s go through them in detail:

1. Can either eGPU enclosure (Sonnet 750ex or Razer Core X) charge your HP Spectre?

Short answer: Yes, but…

Both enclosures support Power Delivery (PD) over Thunderbolt:

Sonnet Breakaway Box 750ex | 85W | Should be sufficient for general use, but not peak GPU+CPU combined load. 
Razer Core X | 100W | Closer to your original 140W PSU. Still not full wattage, but better.

Your HP Spectre's 140W PSU is designed to handle worst-case loads (CPU + GPU full load). In typical use (especially with eGPU offloading GPU tasks), the laptop often draws under 100W.
 

Conclusion:
You can run either enclosure without needing the original charger for most workloads.

Razer Core X gets you closer to native power.
For full performance under sustained load (e.g., heavy CPU and GPU work), you might still want to plug in the native charger via the second Thunderbolt port.

2. Can I safely connect both the eGPU and the native charger? Do I need to disable one power source?

Yes, it’s safe. No need to disable anything manually.

• Thunderbolt and USB-C PD is intelligent—the laptop's charging controller negotiates and automatically chooses the higher wattage or more stable power source.
• The internal power controller will prevent both from feeding full power simultaneously.
• Worst case: it might just pull the majority from the 140W charger and supplement (or ignore) the 85W/100W from the eGPU.

You can monitor this via software (like HWMonitor, HWiNFO, or BatteryInfoView) if you want to see what's being drawn from where.

3. How can I tell if a GPU is "too much" for Thunderbolt 4’s bandwidth?

Great question. Here's how to assess that bottleneck and apply it practically:

Key Specs to Watch:

PCIe Bandwidth | “PCIe 4.0 x16”, “PCIe 3.0 x16” | TB4 offers PCIe 3.0 x4 (~4 GB/s real-world). Any GPU using more than this may be bottlenecked. 
Memory Bandwidth | e.g., “448 GB/s” | Helps understand how much data the card can process vs how fast data can be sent over TB. 
TDP (Wattage) | e.g., 140W, 300W | High TDP cards usually expect more bandwidth. 
CUDA Cores & Clock Speed | More CUDA/RT cores with high clocks = more data to push across TB 

Realistic Threshold:

• RTX A4000: PCIe 4.0 x16, 448 GB/s mem bandwidth, 16GB VRAM — it will be bottlenecked slightly, but still excellent for GIS/3D/CUDA tasks.
• eGPUs typically lose 10–25% performance vs internal x16.

If you're not gaming or rendering in real-time, you're fine. The RTX A4000 is a great fit for eGPU use in spatial workflows—especially at a discount.

 Other good value GPUs:

• RTX 3060 Ti (best cost-to-performance)
• RTX 3070
• RTX A2000 (very power efficient, professional CUDA card)
• GTX 1660 Super (older but good baseline if cost is key)

4. Can I use the onboard Nvidia GPU for the internal screen and the eGPU for external monitors/applications?

Yes, it’s possible with some setup.

Here’s how to make it work:

• Connect the eGPU.
• Plug external monitors directly into the eGPU’s display ports (not via dock or laptop).
• Go to NVIDIA Control Panel or Windows Display Settings:
  • Assign the laptop screen to the internal dGPU (e.g., MX450, Arc, etc.)
  • Assign external monitors (via eGPU) to use the external GPU.
• In Windows Graphics Settings:
  • For Teams, Slack, Outlook, set to “Power Saving” (iGPU or internal dGPU).
  • For GIS, CAD, 3D apps, set to “High Performance” (eGPU).

 Windows will manage GPU contexts per app, and as long as the screens are connected directly to the respective GPUs (internal for built-in screen, external for eGPU), this separation works well.

In Summary, 

• ✅ Yes, both Sonnet 750ex and Razer Core X will charge your laptop to an acceptable degree.
• ✅ No issues connecting your original 140W PSU as well; no manual switching or disabling needed.
• ✅ Use GPU specs (especially PCIe bandwidth & TDP) to gauge TB4 limitations—A4000 is powerful but still efficient for eGPU use.
• ✅ Yes, you can split workloads across internal and eGPU GPUs based on apps/screens, with a bit of setup. 

I hope this helps!

If my response resolves your issue, please click “Accepted Solution” to help others find the answer. Also, don’t forget to click the “Yes” button to say thanks!

Take care and have a great day.

Max3Aj

HP Support

[Subhydro]

Hi Max3Aj,

That is amazingly helpful, and gives me the confidence to make my purchases.

Thank you so much for your help.