KB2264080 is a Hyper-V rollup that includes the fixes documented in the following KBs:
975530 Stop error message on a Windows Server 2008 R2-based computer that has the Hyper-V role installed and that uses one or more Intel CPUs that are code-named Nehalem: "0x00000101 – CLOCK_WATCHDOG_TIMEOUT"
974909 The network connection of a running Hyper-V virtual machine is lost under heavy outgoing network traffic on a Windows Server 2008 R2-based computer
981791 "STOP: 0x0000001a" error message on a computer that has an Intel Westmere processor together with the Hyper-V role installed on Windows Server 2008 SP2 or on Windows Server 2008 R2
So three LDRs are combined into one GDR and everyone using Hyper-V R2 is advised to install this update.