I bought a bunch of Raspberry Pi 3 for a project (I'll post about it soon), I have one spare so I run a kernel compile

/mnt is an old, slow, ugly USB stick I got on a conference, go figure!

$ make -j4 bcm2709_defconfig O=/mnt
[...snip...]
$ time make -j4 O=/mnt
[...snip...]
[...snip...]
[...snip...]
[...snip...]
[...snip...]
H16TOFW firmware/edgeport/boot2.fw
H16TOFW firmware/edgeport/down.fw
H16TOFW firmware/edgeport/down2.fw
IHEX2FW firmware/whiteheat_loader.fw
IHEX2FW firmware/whiteheat.fw
IHEX2FW firmware/keyspan_pda/keyspan_pda.fw
IHEX2FW firmware/keyspan_pda/xircom_pgs.fw
make[1]: Leaving directory '/mnt'

real    110m27.565s
user    372m1.100s
sys     18m31.400s

Not bad, not bad at all! :)