You have two issues here: The ripping speed varies a lot per CD, and when the speed is slow your PC is not responsive.
On a new PC the ripping speed will be limited by the CD/DVD drive. CD quality varies a lot, as does the quality of your CD/DVD drive, so when you rip a CD the drive will copy data as fast as it can reliably read it. A CD that only rips on you PC at 2x might rip much faster in another drive.
The second issue is the unresponsiveness, and I am sorry to tell you that is the result of Windows' DOS heritage, and the way a CD/DVD hardware driver interacts with the PC and Windows. When you have a CD that is hard to read, and is requiring many rereads, it slows Windows to a crawl.