Extreme lag in Blender with AMD Radeon HD 6900


I tried looking through the technical support forum and I couldn’t find an answer to this. I seem to be experiencing a problem identical to nvidia users, which many have posted on the forum about. However, I am using a Radeon HD 6900 graphics card. Blender is extremely slow and I cannot do something as simple as change the size of my objects. My files are very large as I am editing reconstruction of neuronal cells, but we have been able to work on these object files with no issue in the past.

I was wondering if there is a way to speed up Blender, as I notice that, even during the lag, there is only about 5% CPU being used and 5 out of our 64GB of RAM. It seems to be single-threaded, when we evidently need its multithreaded functionality to work on this data set. Any help would be appreciate.


Need more information

are you running windows / linux /mac? what os? what version of blender? what driver version.

You also say your files are very large… are simple files fine? how are your files large? can you optimize them (reducing complexity, changing duplicate objects over to dupligroups etc.etc.etc)