Those two hard drives are essentially the same, except for capacity and manufacturer.
I doubt you would see any difference at all.
Keep in mind that your computer's speed is not much in your hard drive, but is a combination of the CPU, the RAM, the various buses (memory, system, I/O, etc), and finally, the perfomance of the hard drive. A HUGELY faster drive, such as an SSD, would make a very noticeable difference - but is perhaps more than you want to invest in a 7 or 8 year old computer.
A spinning hard drive is not that huge a difference, although a hard drive that is several years old could be changed out for a brand new hard drive. Very often, two identical hard drives, except for age - the newer hard drive will often "feel" faster.
One of your drives may simply be in better condition than the other. I usually "treat" an older hard drive to a full erase, writing zeroes to all blocks. You can do that through an option in your Disk Utility. That will probably give one of your hard drives some slight edge over the other. I couldn't say which one would respond the best, so you would have to try on both.
I would suggest, for your best results, to replace one with a new drive. The system boot drive works much harder than a storage drive, and you would likely see some benefit with a new hard drive for that.
And, you would see more speed (and more expense) by putting an SSD in for your system drive.