SSD drives are solid state and don't have to spin like a regular hard drive. They are blazing fast, and often are used to hold the operating system of a PC, so the boot up is fast.
HDD drives come in different speeds. It's quite likely a new PC will have a higher speed hard drive than an older one. So a new larger drive might actually run faster than an older smaller one.
Any HDD will run more slowly if the disk is fragmented. That used to be something you had to do manually. Windows 10 calls it "disk optimizer" and by default it runs weekly, which should be more than adequate. But you can also run it manually if you want to.
