Furmark is not available for Mac but there are some alternatives that runs on macOS with similar functionality. The best Mac alternative is Cinebench, which is free. If that doesn't suit you, our users have ranked more than 10 alternatives to Furmark and six of them are available for Mac so hopefully you can find a suitable replacement. Other interesting Mac alternatives to Furmark are UNIGINE Benchmarks (Freemium), Novabench (Free), Phoronix Test Suite (Free, Open Source) and GpuTest (Free).
CINEBENCH is a real-world test suite that evaluates your computer's performance capabilities. It's the perfect tool to compare CPU and graphics performance across various systems and platforms (Windows and Mac OS X). And best of all: It's completely free.
GpuTest is a cross-platform (Windows, Linux and Max OS X) GPU stress test and OpenGL benchmark. GpuTest comes with several GPU tests including some popular ones from Windows'world (FurMark or TessMark).