Sansa

I wouldn't use your motherboard for  the digital to analog. I have a Asus b450 Strix gaming - F and it sounds very odd to listen to anything on it. So i went back to an old FIIO $19 DAC.

I also would stop reading into the specs of hardware. You'll get lost in the marketing. About the audio interface. Yes, it's like everything in a bundle. You woudln't need to buy a headphone amp or a DAC, that is unless you didn't like the sound that DAC used. Digital-to-analog conversion is just a statement on what it's doing. The chip used is how it's going to sound.

I wouldn't read also into the high sample rates or bit depths as well. To understand 32 bit, i would google around 32 bit float point. On DAW hardware you would expect marketing for it, but it mostly how all DAW hosts record while in the software. Unless you're trying to listen to 7.3 on some amazing setup, i'm not sure you would ever need anything over 16, 24 bit, at 48kHz / 44.1 kHz.

I'm not trying to confuse you and if i did, sorry. Just trying to help you understand that it's more about personal taste than numbers on a product. I say that as you stated something along those lines with "If i connect that audio interface to my motherboard i will be limited to those 24-bit? if the asus can deliver 32-bit, i dont want to be limited by the audio interface. What should i do then?"

Now i will say that if your headphones are hard to power, you might hear a something different from using a good powered headphone amp. For example, i'm using a

FIIO E09K headphone amp 
FIIo Tascam DAC
AKG K702s
Mackie MR8's Monitors

I also use a DTI dual transformer / isolator. The DTI is to remove any unwanted noise from my setup.

Your best bet, know what you want from your headphones before you purcahse. For example i wanted a flat curve on mine, so i could EQ and mix without the master changing in a car or a different studio. You might want something with more lows, or a different sound altogether. So many online sites with reviews its hard to know what is paid content.

So small tip list

Know what your want in your headphones. (soundstage)
What type of headphones do you like better? (Closed back, open back?)
Please don't get lost into just adding fancy cables to your headphones, it doesn't matter much!
Don't get lost in all the specs.
Only you will know what you like the most. (Listen to your ears!)

There are so many brand loyal, biased sites online now, most channels offer their opinions as facts. best bet, go try a pair in store like a guitar center or something (once they re-open). If you can't wait, than best to find un-biased reviews on the product you're lookng at. That is the hard thing. Most reviews are paid now, so it's to know what is really good from just watching videos.

I tend to agree with Rice, the headphones don't technically need a DAC or amplifier and unless your motherboard audio is actively negatively impacting your listening experience don't worry about it. I'm not a huge fan of onboard audio because my workload requires features that it just doesn't have but truthfully I've found it more than good enough for the basic listening it sounds like you'll be doing.

Also, Homeap5 is completely wrong when they said "Buying good headphones doesn't make you audiophile. Good amplifier and good speakers plus good dac or soundcard can." Nobody should be gatekeeping, being an audiophile just means that you care about sound quality, and being that there is no objective peak for sound quality there can be no objective requirements to be an audiophile. I'm a member of other forums where audiophile can mean anything from that guy with the 30 subs in their car to the purist with a $200K analogue listening room, obviously the priorities of these people will be completely different but they both really care about their subjective ideals of sound quality and are both audiophiles in the rawest sense of the term.

Sloth

Thanks for the answer to all of you.
Why you say the h510 wont get here at all? is there a problem with nzxt? My country is usually half a year or even a year behind new tech products coming
 
Thanks fopr the NR600 recommendation. I really liked it. The thing is it isnt available here (Uruguay)... Theres a lot of offer of sharkoon and cougar cases, but i dont know if those are quality cases... Im done with second class stuff. I want a decent, sleak case that lasts me for a while. 
Im using now an antec GX700, which is a cool case, good airflow, tons of expandability, but having a new system in it, rgb and all, im wanting a glass panel to look at it and not hide the PC under the desk, since the GX700 is looking kinda "childish" to me now,.. so, i was aiming to the looks of a h500 or the said NR600 do have. 
 
 
 
 
 
BTW, i recently looked at a hardware canuks video of the Lian Li LANCOOL II, and i could dig that LOL. Nice case. But again, thats just out, and i have never seen a lian li case here T_T
 
I finally got the h710 from nzxt