Why does a cable standard matter so much?
Short answer: A Thunderbolt 4 (TB4) cable carries 40 Gbps of bandwidth — four times a standard USB-C 3.2 Gen 2 cable — and simultaneously delivers up to 100W of charging power. It uses an identical USB-C physical connector, which means you can accidentally plug in the wrong cable and wonder why your dock is underperforming. Knowing the spec printed on the cable prevents wasted money and frustrating compatibility surprises.
Understanding the cable hierarchy
USB-C (basic) — the cables that come in phone boxes
The cheapest USB-C cables sold in India for ₹150–₹500 typically support USB 2.0 speeds (480 Mbps) and 18W charging. They're fine for charging phones and older laptops. Plugging one into a Thunderbolt 4 dock will work — the connection will fall back to USB 2.0 speeds, making file transfers dramatically slower than the dock's advertised performance. These cables have no Thunderbolt or USB 3.x markings.
USB-C 3.2 Gen 2 — the current mainstream
A properly rated USB-C 3.2 Gen 2 cable runs at 10 Gbps and supports Power Delivery up to 100W. This covers most daily use: charging a MacBook Air or Dell XPS, transferring files at full SSD speeds, and driving one external 4K monitor. In India these cables cost ₹400–₹1,200 from quality brands. Check the packaging for "USB 3.2 Gen 2" or "10 Gbps" — unlabelled cables from market stalls rarely meet spec.
Thunderbolt 4 — when you genuinely need it
Thunderbolt 4 (developed by Intel, found on MacBook M-series, Dell XPS 13/15/17, Lenovo ThinkPad X1 Carbon, HP Spectre x360, Asus ZenBook) delivers 40 Gbps of bandwidth — enough for dual 4K monitors, an external GPU, and a full dock simultaneously. The certified TB4 cable contains active electronics inside the connector housing — it is not just a wire. This is why a passive ₹300 cable cannot achieve these speeds regardless of the port it's connected to. Certified TB4 cables in India range from ₹1,500–₹3,500 for 0.8m active cables.
USB4 Gen 3×2 — the newer sibling
USB4 (note: no hyphen, unlike USB-C) Version 2.0 Gen 3×2 matches TB4's 40 Gbps and is the basis for Thunderbolt 5. Intel now licenses Thunderbolt over USB4, meaning USB4 40G cables can interoperate with TB4 ports. However, not all USB4 40G cables are certified to support every Thunderbolt feature (daisy-chaining, eGPU). When in doubt, buy a cable with the Thunderbolt certification mark rather than relying on USB4 marketing language alone.
The India angle — counterfeit cables
Indian online marketplaces carry a significant volume of cables that claim Thunderbolt 4 or "USB4 40G" on the packaging but are physically standard USB 2.0 wires inside. The tell: genuine TB4 cables are never under ₹1,000 — the active electronics inside cost money to manufacture. If a "Thunderbolt 4" cable is priced at ₹399, it is not a real TB4 cable. Counterfeit cables can also cause intermittent port faults — if your USB-C port starts behaving erratically after trying a new cheap cable, have it checked at a USB-C port repair service before assuming a laptop fault. For a full laptop charging setup, also see our guide on the best USB-C fast-charging cables in India.
Quick reference: which cable for which task?
| Use case | Cable needed | Approx. India price |
|---|---|---|
| Charging only | USB-C with correct wattage rating | ₹400–₹900 |
| Data + one 4K monitor | USB-C 3.2 Gen 2 | ₹600–₹1,200 |
| Thunderbolt dock / dual 4K | Thunderbolt 4 certified | ₹1,500–₹3,500 |
| eGPU / long run (2m) | Thunderbolt 4 active 2m | ₹2,500–₹4,000 |
Indicative ranges as of writing. Verify wattage and Gbps markings on packaging before purchase.
A note from the LRW Engineer Team
We regularly diagnose USB-C port issues that turn out to be cable-induced rather than hardware failure. A counterfeit "TB4" cable that supplies slightly wrong voltage can stress the port's power-delivery controller over time. If your laptop reports intermittent charging or the dock connection keeps dropping, try a verified genuine cable first — it resolves the issue in many cases without a repair visit. When it doesn't, our port repair service can assess the damage. For MacBook owners who also need a dock, pair the right TB4 cable with the advice in our USB-C dock buying guide.