Can HDMI 2.0 Do 4K 120Hz? The Truth Behind the Bandwidth Math

1. HDMI 2.0’s Hard Limits: Why 4K/120Hz Fails

HDMI 2.0’s 18Gbps bandwidth cap is its Achilles’ heel. Let’s break down the numbers:

• 4K/60Hz = 12.54Gbps (Compressed with 4:2:0 chroma)

• 4K/120Hz = 25.08Gbps (Even with 4:2:0 compression)

The verdict:
✅ HDMI 2.0 can handle 4K/60Hz or 1440p/120Hz
❌ 4K/120Hz exceeds its bandwidth by 39% – causing black screens or artifacting.

Real-world test: Connecting an RTX 4080 to LG C2 OLED via Hdmi 2.0 Cable:

• Output set to 4K/120Hz → “Signal Out of Range” error

• Downgraded to 4K/60Hz → stable display.

2. The “Fake 120Hz” Scam: How Sellers Mislead

Beware of cables marketed as:

“HDMI 2.0 Supports 4K 120Hz!”

How they cheat:

• Using chroma subsampling (4:2:0) to theoretically fit 4K/120Hz into 18Gbps

• Reality: Most monitors/TVs don’t accept 4:2:0 at 120Hz – forcing fallback to 60Hz.

Lab data:

3. The Solution: Certified Hdmi 2.1 for True 4K/120Hz

To unlock real 4K/120Hz, you need:

• HDMI 2.1’s 48Gbps bandwidth

• Ultra High Speed HDMI certification (QR code-verifiable)

• Display Stream Compression (DSC) 1.2 support (lossless compression)

Why our cables guarantee performance:

• 24AWG oxygen-free copper cores → minimal signal loss

• Triple-layer EMI shielding → zero interference from routers/phones

• Batch-tested at 48Gbps (per HDMI Forum CTAs)

👉 Pro Tip: Check your device’s HDMI port version!

• PS5/Xbox Series X: Requires HDMI 2.1 ports + cables for 4K/120Hz

• NVIDIA RTX 30/40 GPUs: Use DisplayPort 1.4a if HDMI 2.1 unavailable.

  

  Key Takeaways for Users

  1. HDMI 2.0 ≠ 4K/120Hz: Bandwidth caps at 18Gbps (4K/60Hz max).

  2. Marketing scams exist: “4K 120Hz” labels on HDMI 2.0 cables exploit technical loopholes.

  3. Certification is critical: Only Ultra High Speed HDMI cables ensure 48Gbps throughput.

  4. Future-proof wisely: Hdmi 2.1 Cables work backward-compatible with older devices.