I upgraded from S11-SRU11 to S11U1-SRU1. Until approx. 5 min after reboot, the ethernet performance is as I am used to it before the upgrade, at about 113 Mbps on a e1000g (which is pretty close to the physical maximum). Then suddenly the throughput goes down significantly, and I measure everything between 8 Mbps and 69 Mbps. Rebooting does not help.
After going back to S11-SRU11 via snapshot, the old performance of 113 Mbps is back, and consistenly.
All throughput is measured with nttcp-1.147 on Solaris and PCATTCP-0114 on Windows 7.