https://www.arista.com/en/products/7280e-series
Arista 7280E: Ultra deep 9GB of packet buffers
Total System Buffer
10Gbps: 9x8Gb/10Gb = 7.2 sec
40Bgps: 9x8Gb/40Gb = 1.8 sec
100Bgps: 9x8Gb/10Gb = 0.72 sec or 720msec
QFX10k: up to 100ms per ports ( any ports)
10Gbps: 10Gb/.01sec = 100Gb / 8 = 12.5 GB
40Bgps: 40Gb/.01sec = 400Gb / 8 = 25 GB
100Bgps: 100Gb/.01sec = 1000Gb / 8 = 125 GB
White paper: Packet Buffers In Cloud Network Switches
https://www.arista.com/assets/data/pdf/Whitepapers/BigDataBigBuffers-WP.pdf