Please read this if you're using Iris:

If you're playing this with Iris, you need ADDITIONAL MODS. Alternatively, you can also download a compatible Modpack

What's Optimum Realism?

Optimum Realism is a realistic resource pack that tries to replace Minecraft blocks with their real-life counterparts themselves with a perfect balance between performance and quality, not only does it try to widen the spectrum of imagination between a game and real-life scenarios but also, elaborates on most objects that signify their importance better than we would notice rather than just "adding them" as they would be in real life.

Is it free?

Yes, it is partially. The 64x version of Optimum Realism is free. 128x, 256x and 512x are member-exclusive only. You can access 64x+ versions of Optimum Realism by becoming a member from either of the following at your convenience:-

Most resource packs and shaders can achieve astounding graphics worth applauding, but there has always been a downside to these astonishing, wonderful masterpieces: performance. Optimum Realism can't really change the entirety of that; a coin always has two sides.

But its aim has always been to not only give you the most brilliant-looking graphics possible but also to maintain consistent performance while trying to find a perfect balance between performance and quality. Even though it's still far from completing its aim, it is happening consistently, update by update downloaded by over 3M+ people. Join us in this long but great journey.

The best features possible, all in one pack. You might think, that due to being able to maximize performance, Optimum Realism lacks unique features, but be rest assured, Optimum Realism has the most unique features, barely seen on any other resource pack. One of such feature is depth-write POM, which makes textures interact with each other as seen here, the sand fills the crevices left in the planks, like an actual environment.

690+ PBR textures
Connected textures, custom entity models, and emissive blocks.
Java Edition (Iris + Fabric, Optifine) + Bedrock RTX and VV support
An exemplary balance between quality and performance.
Tons of features like Parallax Occlusion Mapping, Physically Based Rendering, Emission blocks, Depth-write POM, etc.
Updated the with most advanced features.
Over 3M+ downloads all over various platforms.

Optimum Realism will run fine on a decent gaming computer. You don't require an RTX card to run the resource pack(Unless on the Bedrock RTX version). . I'd recommend a pc that has a minimum of 8GB RAM to run the resource pack without lag spikes. A GTX 1050 should run fine on the 128x version.