STREAMER

IME everything makes a difference in the streaming chain.  Many people have gotten considerable improvements by upgrading their streamer’s power supply so that might be something to consider as well.  Best of luck. 

The only answer is to try it yourself. Some people hear a difference, some don't. Don't waste your money because of what someone else says they can hear. 

There are a couple of ways to approach this. One is buy a new cable from a company with a good return policy. Another option is to buy used. If you shop wisely, you can resell it for about what you paid for it. (New cables subsequently sold used take a BIG hit on their price.) 

John Rutan (Audioconecton) believes your best power cord should go to the source first. So, to answer your question- Yes, the power cord will improve the sound quality. 

I would suggest something like the AQ Thunder or Hurricane, which are now priced nicely in the used market. ( I heard them at Audioconnection, and knew they worked wonders).

Bob

Yesterday I replaced the cord for my Lumin T2 with one on those stupidly cheap (non knockoff!) 5N OCC pure silver PCs from Aliexpress.  Think it was ~$60 for a 1.5m length. Low and behold, this new silver PC sounds different.  It sounds more immediate and quick and with a bit more treble extension.  It's kind of impressive actually.  Makes me wonder how far it can go, or if I've already hit diminishing returns.  Of course my brain might just be playing tricks on me, but I'm rolling with it, and the sounds seems to be staying constant.  Pretty impressive bias I'd say!  I'd say try it and give it a shot, with a good return policy (or cheap price) you have little to lose.

Everything makes a difference, but as soix mentioned, a separate linear power supply is another way to go. In my experience it very likely will be more beneficial than just a PC upgrade.