Complete information regarding supported S/390 and zSeries machines can be found in IBM's Redbook Linux for IBM eServer zSeries and S/390: Distributions in chapter 2.1 or at the zSeries page at the developerWorks. In short, G5, Multiprise 3000, G6 and all zSeries are fully supported; Multiprise 2000, G3 and G4 machines are supported with IEEE floating point emulation and thus degraded performance.