I am using a Xinhs 4 core graphene cable on my Timeless today, and I don’t hear a difference. That said, the stock Timeless cable is a silver-plated single crystal copper that is foil wrapped, so 7Hz was trying to make a quality cable for this IEM.
I own a few nice cables, but tend to do so because I liked the way they looked, or measured electrically. I own two Xinhs cables, but the blue one I bought to go with my blue Mele was all about how dope it looked. I am happy to report they both sound great too. This one was a case where I wanted to try out graphene and I have, it is interesting and makes for a light cable.
Usually when I can tell the difference, I can also measure it with a multimeter, so while materials matter it is still about their impact on the electrical signal. When it comes down to best value cable for the performance, I still think the Tripowin Zonie is the best deal at $20 for a 16 core silver plated that is very flexible.
Other people have other opinions, which is cool