The other way of conducting a quick test is to upload a CD to Sooloos using Control:Mac and check Network Utility (in Apps -> Utilities) while doing so. In the Info tab you'll see the Send and Receive errors and any collisions ... change cables and/or switches until the problem stops! grin

This approach does have the advantage of being free.

Office: MacMini + Roon -> MS600 -> AR LS-9 -> M60s (1993 vintage)
Home: [AppleTV -> HD621] + [Roon -> 218] -> G65 -> DSP5200HC + DSP5200s + DSP3200s
Being a JAFA in Auckland, New Zealand