You're remembering it incorrectly.
There were two types of 9500 non-pros. One had an L shape memory layout (2 chips above and beside the GPU), the other had all the memory chips in a row. If it had the L shaped layout, you could flash it to 9700 and unlock all 8 pixel pipelines and the full...
I was never able to find a solution to this.
Having gsync enabled seem to fix the problem in most cases, but not all.
My 100% fix was to replace my 60hz monitor with a 144hz monitor.