Cable Matters 8K DisplayPort 1.4 to HDMI 2.1 Adapter with 4K 240Hz / 8K 60Hz, Unidirectional DisplayPort to HDMI 2.1 Cable Adapter, Supports RTX4080, RX7900, Not Work with PS5/Xbox, No VRR Support

I bought three of these Cable Matters DisplayPort 1.4 to HDMI 2.1 adapters to drive my LG OLED TVs as monitors from an RTX 5080, and they’ve been absolutely flawless. The biggest win? They fully support VRR—and all three arrived preloaded with the 7.02.120_forVRR firmware. I had downloaded the firmware ahead of time expecting to flash them manually, but Windows immediately showed a VRR notification for each one. I verified with the Cable Matters firmware utility that all three adapters already had the correct version installed. The tool is simple and well-designed, so even if I’d needed to update them, it would’ve been easy.I’m running them at 2160p120 HDR RGB 10-bit, and they also handle YCC 4:4:4 perfectly. Since DisplayPort 1.4 is bandwidth-limited, it’s great to see the adapter properly passing through DSC (Display Stream Compression) from the 5080 to the 42" LG C2 without any glitches or image degradation. I’ve paired each adapter with Zeskit 48Gbps HDMI cables, which I highly recommend—this ensures stable bandwidth for 4K120 HDR with RGB 10-bit and VRR without signal drops or handshake issues.Over the past few days of testing, they've been rock solid—no flickering, no handshake delays, and no stability issues through reboots, resolution changes, or long sessions. HDR signal passthrough works flawlessly, with accurate color, proper contrast levels, and clean gradients—no banding or chroma issues observed. These adapters also run cool and feel well-built, with a compact and flexible design that makes them easy to route even in tighter setups without crowding nearby ports.Now that I know these work reliably, I’m planning to expand to a triple OLED setup using three 42" LG C4 TVs as monitors. These adapters are perfect for unlocking full-feature HDMI outputs on NVIDIA cards that typically only offer a single HDMI port—now I can run four displays at full 4K120 HDR with RGB 10-bit and VRR.Can’t recommend these enough.

Did exactly what I needed it to do. No drop in video quality from what I can tell. Easy to use, works completely fine, decent quality especially for the money.

I picked up this Cable Matters 8K DisplayPort 1.4 to HDMI 2.1 adapter to connect my DisplayPort-equipped GPU to my HDMI 2.1 TV, and for the most part, it works as advertised. Build quality is excellent — the braided cable feels durable, the molded strain relief should help it last, and the LED connection indicator is a nice touch. It supports high resolutions and refresh rates, HDR, and surround sound, making it a great option for gaming or 4K/8K media.However, there’s one important technical caveat that isn’t clearly explained in the product specs. While the adapter claims HDMI 2.1 support (8K@60Hz, 4K@120/240Hz), it’s still limited by the DisplayPort 1.4 bandwidth on the source side. That means those higher refresh rates and resolutions often rely on heavy DSC (Display Stream Compression), which can noticeably reduce visual quality, especially in fast-moving content. If you expect full uncompressed HDMI 2.1 performance, this limitation may be disappointing.For reference, my monitor is a Asus 42" 120Hz 4K OLED with HDR and full 10-bit color. On a display of this caliber, DSC would be a gross degradation of quality, introducing artifacts and compression that completely defeat the purpose of such premium image fidelity. Because of that, I will never enable DSC and expect uncompressed signal quality whenever possible.For most users connecting a modern GPU to a high-refresh-rate monitor or TV, it’s still a solid and reliable adapter — just go in knowing that the bottleneck is DisplayPort 1.4, not HDMI 2.1.

I bought this because a lot of reviews said that it supported variable refresh rate. On Linux, AMD GPUs cannot output proper HDMI 2.1 due to HDMI being an awful standard, but I wondered if using a Displayport to HDMI adapter could get around this limitation.When I first took the adapter out of the box, I didn't have a proper HDMI 2.1 cable to test it with, but it did seem to work at 4K YCbCr 120Hz with VRR under Linux on my Dell 4K 144Hz monitor and confirmed that the refresh rate was indeed varying looking at my monitor's OSD. I then tried it with my old Samsung 2018 TV that has the old AMD-specific FreeSync and it did not work correctly in Linux (TV would flicker on and off whenever the frame rate dropped) but this was also true using the HDMI port directly on my GPU, so no fault of the adapter it would seem. I then tried the same on Windows and it worked great. The TV would run with AMD FreeSync with this adapter and with it directly connected to my GPU's HDMI port. Chalking this one up to Linux driver support.I then got a proper HDMI 2.1 cable and hooked it up under Linux. I was able to enable 4K 144Hz VRR mode but it seemed to be in YCbCr mode, but it would flicker on and off. I tried again with Windows and it seemed to work sometimes, but then the monitor would flicker on and off some other times.I then decided to try the firmware update everyone was talking about, but worried that it would just remove VRR capability entirely. Sadly, that's exactly what it did. It seems to be stripping the VRR support from the EDID so neither Linux nor Windows recognizes that the display supports VRR at all. This is unacceptable, taking away functionality that was previously offered with a firmware update is not an acceptable "fix" for flaky VRR support. At very least put it in the firmware release notes that you're intentionally breaking this functionality entirely rather than fixing it. I wish there was a way to downgrade the firmware back to a VRR-supporting one, because a display without VRR is useless for gaming. I tried to ask a question on their site but was unable to create an account, with a "try again later" error. So I can't even ask a question about getting this fixed because their tech support site won't let me register.Also, on Linux it seems to boot up with only 60Hz supported. If I unplug and plug it back in to the GPU, then it supports 144Hz. On the old firmware it would go into YCbCr color mode but on the new firmware it seems to stay in RGB color mode, but without the option to enable VRR now.On Windows with the old firmware, it wouldn't even display a picture when booting up with my Dell monitor attached, regardless of HDMI cable used. I had to plug the monitor directly into the HDMI port of the GPU and then back to the adapter and finally it showed a picture. On Windows it didn't go to YCbCr, it stayed at RGB and let me enable VRR but then started flickering on and off after successfully running the NVIDIA GSYNC pendulum demo (which demonstrates VRR on any GPU, not just NVIDIA). That's when I updated the firmware and now no more VRR at all.If they can't re-add VRR support I will be returning this adapter.