Does your Transcend card support UHS-3? I've used Transcend's 64GB Class 10 UHS-3 cards (link below) on every shoot with my GH4 and I've never had a problem.
This build has some unnecessary components, but it's relatively solid. I've planned a new build for myself since I haven't upgraded my system in almost 4 years. If you wanted to take a look, check out the link - just a note, there's no GFX card on there since I plan on using my GTX 970 from my current build, but if anyone needs a recommendation, go for the GTX 1060 6GB - that seems to be the best Price-to-Performance buy right now.