The sound was crystal clear with noticeable clarity in the highs and better sounding lows in my desktop speakers, used SPDIF connection.

That's a digital connection. It means that the card is doing virtually nothing other than relaying the information from your CPU, from the PCI-E bus, to your speakers. It's quite implausible that the card has any affect on the audio clarity.

Any $30 card with SPDIF output would sound identical.  The only difference in sound is any digital effects that you choose to add or that EVGA chooses to add on your behalf. The digital source from your CPU is the unaltered recording as it was provided to you. Any adjustment of that digital signal betrays the intentions of the artist. If no adjustment is made to the digital signal, the $190 EVGA NU Audio card will sound identical to the off-brand $30 sound card since neither is doing anything other than relaying the information from the CPU, via the PCI-E bus, to a SPDIF connector.

Does the digital SPDIF output of the NU Audio card sound different than the analog output of your motherboard's sound card? Certainly. But that is no longer an apples to apples comparison. One would be a DAC and amplifier process on the motherboard versus a DAC and amplifier process in the speaker/receiver. The quality of each could be very different. On the other hand, if your motherboard has a digital SPDIF output, it will sound identical to the NU Audio's output; the only way it could sound different is if someone is playing tricks with effects.