PC doesn't need that much power to play 4k. And the GT1030 is more than plenty..
What OS are you running ? Do you have the proper codecs installed ? OK, VLC doesn't need any external codecs, but is a little buggy. However, it should be able to play nearly anything you throw at it, assuming your CPU is not way too old.
Assuming Windows 10, you can download the the HEVC codec. Microsoft actually charges a $0.99 now.. go figure.. But, you can follow the link below, and they still have a free version (in theory for OEMs - but seems to install just fine for most), follow the link below, and it will then open the Microsoft store where you can install it from.
Code:
Open it in your browser, and when you hit "get" it will ask to open with store.
HEVC Video Extensions from Device Manufacturer
https://www.microsoft.com/en-us/p/hevc-video-extensions-from-device-manufacturer/9n4wgh0z6vhq?irgwc=1&OCID=AID681541_aff_7593_159229&tduid=(ir_wJC0gNTClQca0BAzqwxkEXPhUkjTGXQhW1412Y0)(7593)(159229)()(UUwpUdUnU56397YYwYd)&irclickid=wJC0gNTClQca0BAzqwxkEXPhUkjTGXQhW1412Y0
Then as a player, I like it simple.. So I use "Media Player Classic - BE". It's nice, lightweight, open source, and free. It is based on the old Media Player Classic, but it is actively updated.
Code:
https://sourceforge.net/projects/mpcbe/
For most media playing needs on Android, I usually default to MX player. However there has been a few files I had issues with (had to play with hw vs hw+ vs sw for audio and video. However in those cases, I've actually used Plex as a local media player, and it works surprisingly well. I've been meaning to spend a little more time trying it out, but haven't find the time yet
Keep in mind that if you are trying to play direct from a USB stick or SD card, then you may be limited by the transfer rate of that medium. Try copying the movie locally to your HDD. There have been some rare cases, that I have seen some people using older "energy efficient" HDD units, which were 5400-5900 rpm, and just had horrible transfer rates, and in many cases would hang for a few milliseconds or even seconds in some cases. So if all else doesn't solve your issues, feel free to post your actual computer spec..
OS, CPU model, amount of Memory, and type/model of HDD.