KVM is really quick on my VT enabled Dual Xeon 5506 system running Open Indiana 151a. I have to say this is very nice work by the Open Indiana / Joyent / Illumos teams! Here’s a screen shot of RHEL 5.5 and Fedora 13 installing at the same time:
Instructions on using KVM in OpenIndiana 151a can be found here. One caveat, in order to use /usr/bin/qemu-kvm, you will need a modern Intel processor that supports the new VT extensions. To find out if you have a compatible processor, first find your processor model (i.e. i5-2500K or E5506). Use prtdiag in a Solaris derivative or dmesg in Linux to find your processor model and then look up the processor in Google. You should find a processor marketing sheet from Intel. If your processor supports the VT extentions, you will see this: