Your question is Performance for Data Visualization. Take a moment with it on the right.
Talk me through your thinking if you like. When you're confident, submit your answer and I'll grade it like a real screen (7/10 or better passes).
How do you approach performance optimization for web applications with heavy data visualization requirements?
Explain a practical, measurement-driven approach covering browser rendering, JavaScript execution, data transfer, memory, and interaction latency. Use Safari and WebKit as a concrete browser target where useful, and distinguish diagnosis from optimization.