I've got my DS10x4Z already for a few years but only now got to check the rise time with a half-way decent square source -- my recently constructed Rb 10MHz source with multiple outputs, among them three pretty fast 74LVC drivers with a symmetrizised (sp?) square. These outputs directly connected to the DS...Z's input via RG58 and a proper terminator result in rise/fall times round about 1.6....1.7ns, single channel enabled. See attached screenshots/files for details. I didn't expect the "lil'Rigol" to be so fast. Impressive!
Cheers,
Tom