Slackware installation (cd1 only, full installation selected)
AMD Athlon 64 3800+ (socket AM2) + 1Gb RAM (PC5300) 

- kvm-8                                                          :  9-10mn
- qemu-0.8.2                                                     : 34-35mn
- qemu-0.8.2+kqemu-1.3.0pre9 (without tmpfs ; with kernel-kqemu) : 29-30mn
- qemu-0.8.2+kqemu-1.3.0pre9 (with tmpfs ; withkernel-kqemu)     : 18-19mn

Command used :
/usr/bin/qemu \
 -m     384     \
 -cdrom CD.img  \
 -hda   HDA.img \
 -boot  $1      \
 -net none