Usb or Optical

All things considered, USB should be better. It does depend on the interfaces though. Optical has the advantage of minimal electrical noise contamination, but is, in general, much higher in jitter. I have had very good results with an MIT optical cable but for your application USB is the way i would go. As I am learning of late, jitter has a serious impact on sound quality, much more so (i would think), than ‘noise’. I’ve now heard a jitter-free signal delivered to a familiar system and the difference when clearing jitter is to me, quite remarkable. To me it would suggest that the digital reconstruction filters of average DACs / digital interfaces get the job a bit messed up. I am now a believer that clock-timing is so important for best results.

Just to throw a monkey wrench into this. Another option that hasn't been mentioned is a second ethernet port on server, this way you avoid the lousy motherboard issues with usb or optical. Simplifies network as you can do server>FMC>streamer/usb renderer or streamer dac. I use this configuration with Sonore OpticalRendu as streamer/renderer. You can also do server>whatever ethernet devices you like. This also eliminates the need for a network switch and the added cabling necessary with it.

When speaking of optical here, I'm not talking about Toslink.

People need to keep this conversation on track. Toslink has no bearing in streaming, toslink is inferior optical connection between two digital devices, generally cd transport. This thread is steaming oriented, we're talking about network optical. Network optical does not add jitter, op has rare optical input streamer dac. If his usb sounds better its because either optical out on server inferior or optical input on streamer dac inferior or combo of both. I'd guess usb on streamer dac being superior as this technology has been around long enough so  most dac manufacturers  allocate most resources here. I've observed usb usually outperforms I2S inputs on most dacs, theoretically I2S should be superior as native protocol within dacs.

I had no idea i could by another card and put in my computer and run the usb out of that for optimal sound, how much better will it sound with this usb card ? im guessing not $400 worth.

I searched to see what this magic card does. Not reading the entire thread But a quick scan tells tme this: there’s alot of misinformation above. Yes, USB out of any computer can be noisy. You need to isolate it. That’’s not $400. There are statements that Windows resamples and modifies the bits. Not necessarily. You need to set volume to 100% and leave it there and use the USB high res profile (driver). On MAc’s there’s a $10 app called bit perfect that is worth every lira.

I would honestly suggest that you buy some books on digital audio and learn about it before you start throwing money around. I think Hans Beekhausen ????? (impossible to spell) does a surprisingly good job in his e-book. Learn the basics. USB can carry noise int he signal and the ground. Isolate it. USB needs a good clock int he DAC - whatever jitter free signal you think you feed it is lost in the buffer. The best way is to have a source --> ethernet --> a bridge --> USB --> isolation --> DAC.

Oh, and I'll re-iterate what i said earlier - given the equipment oyu have, plug it in, make sure your source spits out bitperfect data (lots of messing around in windows, yea!), and enjoy.

Over and out