Reproduction steps:
1. Open attached project "GetPixelsLargeTex"
2. Open scene "ImportBigFile"
3. Hit play, let the scene run in the editor for a few seconds
4. Quit before too much memory is hogged

Notes:
1. Notice that Commit size (in Windos Task Manager) doesn't match neither Reserved Total nor Total System Memory Usage (in the Profiler)
2. See attached image for Task Manager and Profiler Values on my pc (MemoryScreen.png)
3. Not 100% sure that this is a regression, but in 5.0.0b1 Total System Memory Usage and Commit size did match