Quoted from massively user Deliverator:
"THIS IS ALL CAUSED BY BIOWARE IMPLEMENTING REMOTE RENDERING AS A FORM OF COPY PROTECTION. THIS IS THE DIFFERENCE PEOPLE ARE EXPERIENCING BETWEEN THE HIGH SETTINGS DURING BETA AND THE SETTINGS AVAILABLE NOW.
Massively - what you missed is that the High Rez textures worked fine in the Beta. For release, they implemented REMOTE RENDERING. What's actually happening is that they can't handle the network traffic generated by remotely rendering higher rez textures.
Let me repeat - High Rez doesn't work because of anti-piracy DRM shenanigans, not because they're concerned about players' machines. They're remote rendering so people who have purchased the game won't be able to dig through Lucas's precious artwork for their fan sites.
Again - they're remote rendering so you can't 'steal' what you bought already. Its copy protection and they're willing to go so far as to gimp the game and lie to cover it up.
Remote rendering is the cause of all of the frame drops and slow downs as well as advanced rendering features not working, We pay big money to buy the machines that have gigantic pipes between all of our components, especially to the GPUs. Internet throughput is nowhere near the bandwidth on your motherboard."