- For fast internet you need a fast connection with your ISP mostly. Any modern motherboard is not supposed to be a limitation.
- The audio capabilities built into the motherboards are standard. If (listening to them) you feel it's not good enough, you need a separate audio card, but you can always add it later.
- HDMI = 2k, so HDMI is not 4k. 4k is only build into some TV's, not yet into PC's. So that requirement seems unrelialistic.
- MS Office is a separate buy for software, not relevant for choosing hardware.
So it seems a rather cheap motherboard suffices for your needs.
Kees
Hi,
I need professional help to build my new PC with no limitations in specifications , i just need compatibility & durability to be put into consideration & here are my uses for the desktop PC :
1 - All day high speed internet browsing.
2 - All day high speed internet download & upload.
3 - Listening to music (i need a very decent sound blaster)
4 - connecting the PC to my Plasma TV through HDMI cable to watch full HD movies (need the best graphics card to process full HD movies & 4k)
5 - Microsoft office & the likes.
***please note that i want both the graphics & the sound blaster to be built in for ease of use & avoiding any incompatibility issues.

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic