Network connection speed - 100mbps better than 1000mbps?

If you look at many (all?) of the “audiophile” network switches, etc, one common thread is that the connection to the streamer or DAC is at 100mbps (megabit), not 1000mbps (gigabit).

Now I have not tried any of these devices, but it is not completely unreasonable that higher speed produces more electromagnetic noise. Since 100mbps is more than enough for these devices, maybe using that is beneficial.

So here’s the kicker: If you connect your ethernet cable to the “loopback” connector in your dCS Streamer/DAC instead of the standard connector, you will force the network switch to use 100mbps (all network switches adapt to the speed of the device connected to that port).

Something to experiment with?

Been there, done that. No difference.

Such minute “Electromagnetic noise” variances on the external Switches and on the PHY chips within the dCS unit do not jump to where the actual stream decoding happens, on the S800 TI ARM Cortex chip.


The funny thing is that the StreamUnlimited Stream800 board inside the dCS units (the so called network board) internally works/ is interfaced at just 10/100 Mbit/s.

StreamUnlimited-Stream800.pdf (250.8 KB)

With my Melco S100 switch I prefer the “slower” output. Not a huge difference.

Not quite actually Erno.

There’s a 10/100 Ethernet transceiver (PHY) built onto the S800 board itself, but the S800 also supports a GbE PHY (that “RGMII for 2nd Ethernet…” on the data-sheet) via an external 10/100/1000 Ethernet Transceiver within the dCS units.

I posted previously, w.r.t the loop port, and the specific transceiver chips used;

(By the way, you attached the older/original S800 data-sheet, not the specs of the current boards).

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Thanks Anup,

I have read the part on RGMII ( Reduced gigabit media-independent interface). What could be the reason that they use this, rather than a regular 10/100/1000 physical transceiver?

Edit: I think I found why:

RGMII, Reduced Gigabit Media-Independent Interface, is an interface standard between a FPGA and an Ethernet PHY supporting gigabit Ethernet. RGMII is an alternative to GMII with a reduced number of signals.

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Yes, to reduce the number of interface pins required on the S800 board that interfaces it to the rest of the system :+1:t2:

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