The LZMA benchmark shows a rating in MIPS (million instructions per second). The rating value is calculated from the measured speed, and it is normalized with results of Intel Core 2 CPU with multi-threading option switched off, and measured with old version of 7-Zip.
The test data that is used for compression in that test is produced with special algorithm, that creates data stream that has some properties of real data, like text or execution code. Note that the speed of LZMA for real data can be slightly different. The data in benchmark workload is too artificial and is more random than real world data.
Compression speed strongly depends from memory (RAM) latency, Data Cache size/speed and TLB. Also it uses simple 32-bit integer instructions: "shift", "add", "multiply" and other. Out-of-Order execution feature of CPU is also important for that test.
Decompression speed strongly depends on CPU integer operations. The most important things for that test are: branch misprediction penalty (the length of pipeline) and the latencies of 32-bit instructions ("multiply", "shift", "add" and other).