AMD claims +35% IPC improvements in that specific benchmark, due to improvement in the AVX512 pipeline.
Overall GB6 improvement is likely around 10-15% only because that's how much IPC improved while clock speed remains the same.
The real issue is that most code people run doesn't use very much SIMD and even less uses AVX-512.
Overall GB6 improvement is likely around 10-15% only because that's how much IPC improved while clock speed remains the same.