Literally the only thing that has changed in the time these images were taken is the fact that Windows Vista SP1 RTM (6001.18000.amd64fre.longhorn_rtm.080118-1840) was installed. Image on left was taken directly before installation, second one directly after.

My question is, could SP1 really have caused this? And would removing it really fix it? Isn't it meant to improve performance? Because all I've noticed so far is the fact that system properties displays amount of system memory in GB rather than MB and a much longer boot time.