Real-World Performance Gains

• NAS File Transfers: Copy a 100GB 4K video folder in ~5 minutes instead of ~13 minutes
• Multi-Gig Internet: Actually use your full Virgin M500 (500 Mbps) or BT Fibre 900 speed
• Gaming Downloads: 50GB game downloads finish in ~3 minutes instead of ~7 minutes
• Network Backups: 1TB backup completes in ~53 minutes instead of ~2.2 hours

Use Cat6 Ethernet Cables or Better: To achieve reliable 2.5 Gigabit speeds, you need proper cabling infrastructure. We strongly recommend Cat6, Cat6a, Cat7, or Cat8 Ethernet cables for all 2.5GbE connections.

Recommended Cable Types:

• Cat6 (Category 6): Our minimum recommendation. Supports 2.5GbE up to 100 metres with excellent signal quality. Widely available, affordable, and perfectly suited for home and office 2.5GbE deployments. This is the sweet spot for most users.
• Cat6a (Category 6a): Enhanced shielding and higher frequency rating (500 MHz vs 250 MHz). Supports 10GbE up to 100 metres, so 2.5GbE performance is guaranteed even in electrically noisy environments. Excellent future-proofing choice.
• Cat7 (Category 7): Shielded cable supporting up to 600 MHz. Provides even better noise immunity, particularly useful near power cables or in dense cable bundles. Premium option for professional installations.
• Cat8 (Category 8): Data centre-grade cabling supporting 25/40 Gigabit. Overkill for 2.5GbE but provides maximum headroom and shielding. Most expensive option.

Why Not Cat5e? While Cat5e (Category 5e) cables are technically rated for 2.5GbE at shorter distances (typically under 30-50 metres), performance degrades with cable length, electrical interference, and manufacturing quality variances. For reliable, long-term 2.5GbE operation, Cat6 is the minimum we recommend. The small price difference between Cat5e and Cat6 is worth the performance confidence and future-proofing.

Q: What Ethernet cables do I need for 2.5 Gigabit speeds?

A: We strongly recommend Cat6 Ethernet cables or better (Cat6a, Cat7, Cat8) for reliable 2.5GbE performance. While Cat5e is technically rated for 2.5GbE at shorter distances, Cat6 provides much more reliable signal quality, especially over longer cable runs up to 100 metres. The small cost difference between Cat5e and Cat6 is worth the performance confidence and future-proofing. Look for cables clearly labelled “Cat6” or “Category 6” — they’re widely available from retailers like Amazon, Screwfix, or your local computer shop.

Q: Will I actually see faster internet speeds with my Virgin/BT/Sky connection?

A: If your internet connection exceeds 1 Gbps, or even approaches it, yes absolutely. Virgin Media’s M500 package provides 500 Mbps, and their Gig1 package delivers 1130 Mbps. BT Full Fibre 900 provides 900 Mbps. With a standard 1 Gigabit Ethernet card, you’d be artificially limited to ~940 Mbps maximum even if your connection is faster. This 2.5 Gigabit card ensures you get the full speed you’re paying for. Even with connections under 1 Gbps, the extra headroom provides better performance stability and lower latency.

Q: Does my router or switch need to support 2.5 Gigabit Ethernet?

A: For connections running at full 2.5 Gbps, yes — both ends of the connection need 2.5GbE capability. If your router/switch only has 1 Gigabit ports, the card will auto-negotiate down to 1 Gbps (still works perfectly, just not at 2.5 Gbps speed). Many new routers from TP-Link (like the Archer AX73), Asus (RT-AX86U), Netgear, UniFi Dream Machine series, and QNAP/Synology NAS devices now include 2.5GbE ports. Affordable 2.5GbE switches are also widely available from TP-Link, TRENDnet, and QNAP starting around £40-60 for 5-port models.

Q: How much faster will my NAS file transfers be?

A: In real-world testing, 2.5GbE delivers approximately 2.5× the throughput of Gigabit Ethernet, though actual speeds depend on your NAS drives and network conditions. Here are typical examples:

• 1 GbE: ~110-117 MB/s (megabytes per second)
• 2.5 GbE: ~280-290 MB/s (megabytes per second)

Practically speaking: A 100GB 4K video project that took 15 minutes to transfer now takes 6 minutes. A 500GB photo library backup that took over an hour now completes in 30 minutes. The time savings compound rapidly when you’re doing this multiple times per day.

Q: Will this work in my PCIe x16 slot (normally for graphics cards)?

A: Yes, absolutely! PCIe is both electrically and physically backwards compatible. A PCIe x1 card like this one works perfectly in any PCIe slot — x1, x4, x8, or x16. This is particularly useful in systems where the dedicated x1 slot is blocked by a large graphics card or where only x16 slots are available. The card only uses x1 bandwidth (which is more than sufficient for 2.5GbE), so there’s no performance penalty to using a larger slot.

Q: Do I need to install drivers?

A: Windows 10 and Windows 11 include RTL8125B drivers built-in and will auto-detect the card when you first boot up. The drivers install automatically and the card should work immediately. For absolute best performance and latest features, you can optionally download the newest drivers from Realtek’s website. Linux users: the RTL8125B is supported natively in kernel 5.9 and above (any recent distribution like Ubuntu 20.04+, Fedora, Debian, etc. includes support out of the box). Mac OS also includes native support in recent versions.

Q: Will this fit in my small form factor PC (Dell OptiPlex, HP EliteDesk, etc.)?

A: Yes! The card includes both standard-height and low-profile brackets. For small form factor (SFF) systems like Dell OptiPlex SFF, HP EliteDesk SFF, Lenovo ThinkCentre compact desktops, simply remove the standard bracket and install the included low profile bracket before inserting the card. Works perfectly in mini-ITX cases and compact workstations. Note: Ultra-small “micro” or “tiny” PCs (like OptiPlex Micro) typically don’t have any PCIe expansion slots at all — check your system specifications first.

Q: Can I use this with my existing motherboard’s built-in Gigabit Ethernet?

A: Yes! Both network cards can be active simultaneously. Your system will show two network adapters — one at 1 Gbps (your onboard Ethernet) and one at 2.5 Gbps (this card). You can:

• Use the 2.5GbE card for your primary high-speed connection (NAS, internet)
• Use the 1 GbE port for a secondary network or management interface
• Set up link aggregation/teaming if your switch supports it
• Have redundant network connections for reliability

Q: Is 2.5GbE fast enough for 4K video streaming and editing?

A: Absolutely! 2.5GbE provides approximately 280-290 MB/s (megabytes per second) of actual throughput. Here’s what that means for video:

• 4K streaming: Typical 4K video bitrates are 25-100 Mbps — 2.5GbE can handle dozens of simultaneous 4K streams
• 4K editing: Editing 4K 60fps footage from network storage works smoothly with 2.5GbE
• 8K editing: Even 8K footage (which can be 400-600 Mbps) is manageable, though 10GbE would be ideal for heavy 8K work

For context: a single 4K HDR Blu-ray quality stream uses about 50-80 Mbps. 2.5GbE is 2500 Mbps, so you have massive headroom.