Review on Cable Matters 3-Pack 48Gbps Ultra HD 8K HDMI Cable 6.6 ft / 2m - 8K @120Hz, 4K @240Hz, HDR Support - PS5, Xbox Series X/S, RTX3080 / 3090, RX 6800/6900, Apple TV, and More by Ken Hamdan

TLDR: Initially 6 of 6 cables failed diagnostics. I sent all 6 cables back to Cable Matters. Cable Matters sent me 3 new cables free of charge and told me to try again. 2 cables still failed (3rd not checked). I contacted Denon support about my AVR-X4700H receiver and got no help because they said they don't support HDMI diagnostics for end users. Cable Matters sent me videos of testing they did in their lab using an identical Denon receiver and advised me to abruptly power cycle the receiver before entering the HDMI diagnostics menu. It worked and now the 2 cables I tested before are now every time, if they pass 40Gbps 8k diagnostics. So thank you Cable Matters for contacting us by phone and email as they were very concerned about this review and wanted to investigate further. No thanks to Denon support. Original comment: I bought 2 packs of these "8k, 48Gbps" cables and connected all 6 to my Denon AVR-x4700h receiver's onboard 8k HDMI diagnostics and each of them failed 8k. part of the exam. I sent them all back for a refund. Avoid Avoid Avoid! Save money and buy REAL CERTIFIED 8k cables. Oh wait, there are currently no officially certified Ultra High Speed cables on the market. Basically this means that all 8k cables currently on the market are sold by scammers who circumvent the problem by telling you "we tested them". which means literally nothing and/or offers a refund too. I bet most people buying 8k cables now don't have the right equipment to test non certified cables and use them mostly for 4k content and think they can validate their video resolution requirements in the future, But, you know what? These people are being deceived. Update: August 31, 2020 Cable Matters support contacted me to say they have multiple Denon AVR-x4700h receivers in multiple labs that they are seeing test results of their own cables through Denon. integrated diagnostics. They also sent me a free pack of new 8k cables and asked me to test it again. I ran another test with at least one of the new cables and again got conflicting but mostly unsatisfactory results. I've looked around the internet and found other owners of the same Denon receiver who have had very conflicting test results for other brands of 8k cables. So either the Denon receiver is having trouble consistently performing these tests, or these uncertified cables really are snake oil. To be honest with this seller and to be as objective as possible, I contacted Denon support to see if there were any known issues with 8k HDMI testing. I have increased my rating to 3 stars, until I get a response from Denon and provide further updates. something they support for end users but only for installers and repair partners etc. So I took Cable Matters advice and abruptly power cycled my Denon receiver before entering the HDMI cable diagnostics menu. It worked in the end and I now keep getting 100% transfer results between multiple cables they sent me for free. I also connected 2 of my old HDMI cables right after that and one of them stopped working at 18Gbps and the other stopped working at 40Gbps which is weird but hey I'll take it for now. I have increased my rating to 5 stars, because I have no other testing options other than my receiver and because Cable Matters helped me troubleshoot using their own receiver in their lab and sent me a video of the results. I have yet to report