I installed CentOS6 with the xen4centos set of packages; then I tried to install KVM (for performance comparison), I got the following error in YUM: --> Processing Dependency: /usr/share/gpxe/e1000-0x100e.rom for package: 2:qemu-kvm-0.12.1.2-2.415.el6_5.4.x86_64 Package gpxe-roms-qemu is obsoleted by ipxe-roms-qemu, but obsoleting package does not provide for requirements I manually downloaded the gpxe package and installed it with no problems, so there are no actual conflicts in the files. Thus, ipxe probably *shouldn't* obsolete gpxe -- there are no conflicts between the two, and ipxe doesn't provide what gpxe does. If I had already installed KVM, and was toying with the idea of giving Xen a spin, this may have been enough to deter me. I checked with the XenServer guys, and their version of ipxe doesn't obsolete gpxe; so that must have been something that was introduced in CentOS. -George