At their core, all three models do the same thing: they sit between source and display, offer the source a selected EDID and trigger an HPD event when that EDID changes. The difference lies in bandwidth, and therefore in which video formats they can pass. So choose based on the highest format your chain has to carry.

Comparison at a glance

FeatureDr HDMI (original)Dr HDMI 4KDr HDMI 8K
HDMI version1.4a2.0b2.1
Bandwidth2.25 Gbps · 225 MHz18 Gbps · 600 MHz48 Gbps · 1500 MHz (FRL6)
Maximum video1080p60 12-bit · WUXGA 1920×1200 · 2K4K60 · 3840×21604K120 4:4:4 10-bit · 8K60 4:2:0 10-bit
EDID banks8: 5 presets, 2 programmable, 1 sink copy40: 8 FHD, 24 UHD, 7 programmable, 1 sink copy100 tables: 10 custom, 90 predefined
HDR and Dolby VisionNoHDR10, HDR10+, HLG, Dolby Vision and LLDVHDR10, HDR10+, HLG, Dolby Vision and LLDV, plus VRR and ALLM
Audio (pass-through)Dolby TrueHD · DTS-HD Master AudioDolby Atmos · DTS:X · Dolby TrueHD · DTS-HD MADolby Atmos · DTS:X · Dolby TrueHD · DTS-HD MA and more
Controls3 buttons · 8 bank LEDs · Windows software via USBRotary button · Windows software via USB · RS232Rotary switch with OLED · web server via RJ45 · IP/Telnet
PowerVia HDMI or USBUSB power adapter (included)5V 2A via USB-C
Size60 × 40 × 20 mm · 50 g60 × 40 × 20 mm · 50 g100 × 60 × 22 mm · 120 g

Sources: HDfury's official specifications for the Dr HDMI and the Dr HDMI 4K, and the Dr HDMI 8K knowledge base (manual Rev 1.2). In-depth information on the newer models: drhdmi4k.com and drhdmi8k.com.

When is the original Dr HDMI enough?

When nothing in your chain goes above 1080p60. Think of older TVs and projectors, Full HD installations, AV distribution at 1080p, 3D in Full HD, or locking a source to 1080i, 720p or 480/576p. For those chains, the 225 MHz of the original model is more than enough.

A newer model is no improvement in such a chain. It does the same job, only with bandwidth and features you do not use. So do not choose the newer model because it is newer, but because your chain needs something it offers.

When should you choose the Dr HDMI 4K?

When you want to send 4K60 with HDR, Dolby Vision or LLDV through the chain, up to 18 Gbps. That is the HDMI 2.0b level: most 4K media players, Blu-ray players and set-top boxes. The 4K also has a few features the original lacks, even if you stay in Full HD: EDID banks with full audio, 5.1 or stereo, an HTPC mode that hides the display status from a PC, a +5V injector for active cables and RS232 for control systems. If you need one of those features, the 4K is the better choice. All about the Dr HDMI 4K on drhdmi4k.com ↗

When should you choose the Dr HDMI 8K?

When you need HDMI 2.1 features: 4K120, VRR and ALLM for consoles and gaming PCs, or 8K60. The Dr HDMI 8K also has an OLED display and a web server for detailed EDID editing and for seeing which signal comes in. That also makes it handy for anyone who has to test many HDMI chains. All about the Dr HDMI 8K on drhdmi8k.com ↗

Does firmware or software from one model work on another?

No. Each model has its own firmware and its own EDID Utility. For the original Dr HDMI, only use the files on the download page.