How does ECC RAM performance compare to consumer RAM?

Expect slower speeds and worse latency with ECC. Most DDR4 ECC sticks max out at 3200MHz CL22 or 2666MHz CL19, while your current 3200 CL16 consumer RAM is faster. Consumer RAM is binned for speed and tight timings; ECC RAM is binned for stability and error correction, so you’re taking a step backward in performance.