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Do External Graphics Cards Work for Laptops? eGPUs Explained for UK Users
September 11, 2025
The world of laptop computing in the UK has been transformed by external graphics processing units (eGPUs). Before these innovative devices arrived, gamers, creative professionals, and other high-performance computer users across Britain had to rely on bulky desktop systems for intensive computing needs. Now, eGPUs allow laptop users to achieve desktop-class performance for gaming, 4K video rendering, and AI workloads—though with important considerations about performance and cost that every UK buyer should understand.
The short answer: Yes, external GPUs work with laptops, but with important caveats about performance and cost that every buyer should understand before investing.
These components are rapidly gaining popularity amongst UK tech enthusiasts as one of the most effective laptop graphics upgrade options, establishing a devoted fanbase from London to Edinburgh.
This comprehensive guide explores the current state of external graphics cards for laptops in 2025, addressing whether they truly deliver on their promises and examining how eGPUs function, setup requirements, real-world performance benchmarks, compatibility challenges, and practical use cases for UK users.
How External Graphics Cards Work with Laptops
An eGPU setup transforms your HP laptop into a desktop-class workstation, but understanding the technology is crucial before investing.
An external GPU (or eGPU) setup consists of an eGPU box, a desktop-grade graphics card, and a laptop with Thunderbolt connectivity. Most eGPU boxes also come with a built-in power supply and device ports for USB, Ethernet, and additional displays. Once you dock your laptop to an external monitor, you’ll transform it into a desktop replacement that’s capable of running high-end games, professional creative software, and compute-intensive applications.
Key Components Explained
- eGPU Enclosure: Houses the graphics card and provides power
- Desktop Graphics Card: The actual GPU (NVIDIA RTX 40-series, AMD RX 7000-series)
- Thunderbolt Connection: The data highway between laptop and eGPU
- External Monitor: Essential for optimal performance (connecting directly to the eGPU)
Thunderbolt Connections: Which Version Do You Need?
When it comes to connecting your laptop to an eGPU enclosure, there are three main Thunderbolt standards. Each comes with its own power delivery and bandwidth capabilities that UK users should understand.
Thunderbolt 3 (2015)
The most widely compatible option with 40 Gbps bandwidth, 100W power delivery, and support for 4 PCIe 3.0 lanes. This represents only 25% of a desktop PCIe x16 slot’s bandwidth, creating the biggest performance bottleneck.
Thunderbolt 4 (2020)
Maintains the same 40 Gbps bandwidth as TB3, but adds better reliability, cross-device compatibility, and enhanced security features. It also supports 100W charging and guarantees 4K display compatibility.
Thunderbolt 5 (2024)
The latest-generation connection offering 80 Gbps bandwidth (with Bandwidth Boost mode reaching 120 Gbps), up to 240W power delivery, and native support for multiple 4K or 8K displays. This is the best option for minimising eGPU performance bottlenecks.
Setting Up an External GPU: What You Actually Need
Before you set up your eGPU, here’s your complete shopping list for UK users:
Essential Requirements
- Thunderbolt 3/4/5 port on your laptop
- eGPU enclosure (budget £200-600)
- Desktop graphics card (budget £300-1500+)
- External monitor (for optimal performance)
- Updated drivers and BIOS
Detailed Setup Considerations
Thunderbolt Port Check: Verify your laptop has a Thunderbolt port (not just USB-C). Look for the lightning bolt symbol next to the port. Many HP business laptops come equipped with Thunderbolt connectivity.
eGPU Enclosure Selection: Choose an enclosure that provides sufficient power for your chosen graphics card. A high-end RTX 4080 needs different power requirements than a mid-range RTX 4060.
Graphics Card Compatibility: Purchase a full-size desktop graphics card. The best current options are NVIDIA RTX 40-series or AMD RX 7000-series cards.
Monitor Connection: Connect your display directly to the eGPU’s video outputs, not your laptop’s built-in screen. This avoids major performance penalties. Consider pairing with HP monitors for optimal compatibility.
Software Updates: Update your laptop’s BIOS, Thunderbolt drivers, and operating system before installation.
Step-by-Step eGPU Installation Guide
Follow this comprehensive installation guide for UK users:
Installation Steps
Step 1: Verify compatibility between your laptop’s Thunderbolt port and chosen eGPU enclosure.
Step 2: Install the graphics card in your eGPU enclosure. Insert the card firmly into the PCIe slot and secure it with the provided screws.
Step 3: Connect the eGPU enclosure to your laptop using the appropriate Thunderbolt cable (included with most enclosures).
Step 4: Connect the power cable to your eGPU enclosure and power it on.
Step 5: Boot your laptop and check Device Manager (Windows) or System Information (Mac) to verify the GPU is detected. Install GPU drivers if not automatically downloaded.
Step 6: Connect your external monitor directly to the eGPU’s video outputs and set it as your primary display.
Step 7: Test performance with your intended applications. Run benchmarks or games to verify everything functions correctly.
Common Challenges and Solutions
Laptop Doesn’t Recognise GPU
Most modern Windows 11 laptops automatically detect eGPUs, but if yours doesn’t: Enable the Thunderbolt device in BIOS settings and manually download GPU drivers from NVIDIA or AMD’s websites.
Dealing with Old Driver Conflicts
Clean driver installation prevents conflicts. Use Display Driver Uninstaller (DDU) to remove old GPU drivers before installing new ones for your eGPU.
GPU Fails to Power On
Power supply mismatch is the most common cause. Verify your eGPU enclosure provides sufficient wattage for your graphics card. High-end cards like RTX 4080/4090 need 650W+ enclosures.
Poor Performance Issues
Performance issues usually stem from using your laptop’s internal display. For best results, always connect an external monitor directly to your eGPU and set it as the primary display.
Performance Reality Check: Real-World Numbers
eGPUs deliver impressive performance gains, but with measurable limitations compared to desktop setups that UK buyers should understand.
Gaming Performance Benchmarks
- Desktop RTX 4070: ~100% performance baseline
- eGPU RTX 4070 (external monitor): ~85-90% of desktop performance
- eGPU RTX 4070 (laptop screen): ~70-80% of desktop performance
The performance gap comes from Thunderbolt bandwidth limitations. Even Thunderbolt 5’s 120 Gbps can’t match a desktop PCIe x16 slot’s 256 Gbps bandwidth.
Content Creation Performance
Video editing, 3D rendering, and AI workloads see smaller performance penalties (typically 5-15%) because these tasks aren’t as bandwidth-sensitive as real-time gaming.
Specific Use Case Performance
- 4K video editing: 90-95% of desktop performance
- 3D rendering: 85-95% of desktop performance
- Gaming at 1440p: 80-90% of desktop performance
- Gaming at 4K: 85-92% of desktop performance
Even the top-of-the-line Thunderbolt 5 eGPU, with speeds reaching 120 Gbps, won’t match the speed of a desktop’s PCIe x16 slot. As a result, you can expect some performance loss in an eGPU compared to a desktop. This translates into a 10-20% performance drop for gaming—and this may be even greater if you’re using your laptop’s built-in display.
When it comes to video editing, 3D rendering, and high-intensity AI workloads, you’ll be able to achieve PC-like performance. Bandwidth bottlenecks shrink to nearly zero here, since these aren’t real-time tasks.
Understanding eGPU Costs in the UK Market
Budget Considerations for UK Buyers
The total investment for a complete eGPU setup in the UK typically ranges from £600-2000+, including:
- Entry-level setup: £600-900 (budget enclosure + RTX 4060)
- Mid-range setup: £900-1400 (quality enclosure + RTX 4070)
- High-end setup: £1400-2000+ (premium enclosure + RTX 4080/4090)
This cost analysis helps UK buyers understand whether an eGPU investment makes financial sense compared to purchasing a dedicated gaming desktop or high-performance laptop.
Should You Buy an eGPU in 2025?
eGPUs make sense for specific users, but aren’t the right solution for everyone in the UK market.
You SHOULD Consider an eGPU If
- You have a premium laptop with Thunderbolt 3/4/5
- You need occasional high-performance graphics for work or gaming
- You want to extend your current laptop’s lifespan
- You have a dedicated workspace with external monitors
- You value the flexibility of a portable setup
You Should AVOID eGPUs If
- You’re on a tight budget (total cost often exceeds £800)
- You need maximum portability
- You game primarily on your laptop’s built-in screen
- A dedicated gaming laptop would cost less than your eGPU setup
- You require consistent maximum performance
Alternative Considerations for UK Users
High-performance gaming laptops may provide better value and performance than an eGPU setup for many users. Consider HP’s OMEN series or other dedicated gaming solutions before investing in external graphics.
For professional users, HP’s ZBook workstation series offers built-in high-performance graphics that eliminate the need for external solutions whilst maintaining full portability.
HP’s eGPU Philosophy and Future Outlook
Rather than competing in the crowded eGPU enclosure market, HP focuses on creating laptops that work flawlessly with existing eGPU solutions whilst offering superior built-in graphics performance in their gaming and professional lineups.
HP’s approach recognises that whilst eGPUs serve specific use cases well, many users achieve better results with purpose-built hardware. The company’s business laptops provide excellent eGPU compatibility for users who need occasional graphics acceleration, whilst their gaming and workstation lines offer integrated high-performance graphics for users with consistent demanding workflows.
Conclusion: Making the Right Choice for Your Needs
The bottom line for UK users: eGPUs are powerful tools for specific use cases, but carefully calculate total costs and performance expectations before investing. They excel at extending the lifespan of premium laptops and providing occasional high-performance graphics capabilities, but may not be the most cost-effective solution for users with consistent demanding workflows.
Consider your specific needs, workspace setup, and budget before deciding between an eGPU solution and HP’s range of high-performance laptops designed for gaming, creative work, and professional applications. The right choice depends on balancing performance requirements, portability needs, and total cost of ownership.
For UK users seeking maximum flexibility, an eGPU paired with a premium HP laptop offers the best of both worlds—ultraportable computing when needed and desktop-class performance when docked. For users with consistent high-performance needs, HP’s dedicated gaming and workstation laptops provide superior value and reliability.
