Deformities

It has been a long couple months. I ordered a big arcade to be built and 6 weeks later, I got it. It was running mgalaxy 1.0, had maybe 400 roms between 6 platforms and it was running a pentium 4, on ddr2. Obviously having such a nice cabinet with such low powered PC gear isn't really acceptable. So, i went back to the city for another big day finding all bibs and bobs to upgrade the arcades hardware. Turns out i should have looked inside that PC, it had a 6-pin power connector etc making upgrades very hard. A simple cable from china fixes it but 2-3 months wait so, im running 2 psu's on it. The same day, i'd purchased launchbox and created a sub for emumovies. Got the launchbox lifetime version & emumovies for a year. And this leads us to my current problems. I haven't been able to import a single rom without it erroring on any arts (even while using emumovies) trying to download - i've so far tried snes and n64. It is tediously slow as well. Watching 1 rom take 5 hours to get 7 bits of art media while erroring 50% of them is not satisfying, then you realize it just stopped downloading them ages ago. So you try again but the issue persists. I'm running 4G internet and get around 30-40mbps/3-4mb/sec download speed so it shouldn't be internet speed. This issue has persisted for both n64 and snes romsets i've tried so far. I can't even think of importing mame being i have a 12k romset of that as well and these smaller sets are having such dramas. Any ideas? Edit: it may not be relevant but the pcs specs inside the arcade is an i5 6500, 12gb DDR4, 240GB SSD, 2gb GTX 960 and 4G internet which doesn't have issues generally speaking on the web/games/pings etc, everything is normal.