I was hired by SONY at one point to help optimize a piece of video editing software that the outsourced team had created and could not figure out how to make it

I was hired by SONY at one point to help optimize a piece of video editing software that the outsourced team had created and could not figure out how to make it a) go faster and b) use less RAM. This is back when 16GB was on the upper end of what workstation class machines could handle. The desktop application, written in an early 2004-ish version of C# and .NET regularly brought the workstations to their knees and thrashed memory and pegged the CPU when large 1080p images were being loaded in or moved around. Each RGBA image, stored as a PNG on the HDD, was loaded in, each RGBA 32-bit unsigned integer was unpacked into its attendant R, G, B, and alpha components into 32-bit unsigned integers themselves, which were then stored in an Int (boxed the native to a non-native type) which were then appended to a dynamically allocated at read time ArrayList. Deep copies were made of each image any time one of them was resized or manipulated, keeping the original untouched image in RAM in case it was needed. A copy of the image before transformation was stored on the Undo stack. And the 1080p working surface of the screen was super-sampled at 8x resolution to support defringing of images when layered. All stored as 8-bit RGBA components in boxed 32-bit integers in a dynamically allocated ArrayList.