Software is much, much more bloated today than it was in 2005. 64-bit CPUs were available, but not quite mainstream yet. A "high end" consumer system had a couple gigabytes of RAM and chipset limitations generally capped you out at 4 or 8 gigs. You were lucky to have two CPU cores.

If you took today's software and tried running it on a memory constrained, slow, 2005 era system, you'd be in for some pain.