There's a quote I heard somewhere: "A given speed of computer is available from Cray in 1980 for $10,000,000, from Sun in 1990 for $100,000, from Dell in 2000 for $1000, and from Oxfam in 2010 for $10."
As for the Sun, using SCSI disks and a decent OS more or less compensated for limitations similar to Dell's circa 2000 PC.