[minnesota_bound]

Cost of upgrade from $43 ram memory to $60 for 500gb SSD or total $250 for 8gb ram and 1tb SSD and $10 external enclosure (may need 2).

Manual: https://downloads.dell.com/manuals/all-products/esuprt_laptop/esuprt_latitude_laptop/latitude-e6420_owner%27s%20manual_en-us.pdf

Pop in and out. Shows how to mirror the hard drive.
External $10 enclosure: https://tinyurl.com/y4pyvxm9

Dell Latitude E6420 Upgrading to a New SSD
https://www.youtube.com/watch?v=4NQjieKCtf8

Price of SSD $60 for 500gb and $110 for 1tb
SAMSUNG 870 EVO 500GB 2.5 Inch SATA III Internal SSD (MZ-77E500B/AM)
https://tinyurl.com/k6s2yp9s

To find details on your model.
On screen in setup - F2 at power up.

The memory configuration tested for this model is DDR3 1333MHz DIMM (2 DIMM slots)
Min 2GB to Max 8GB memory

Crucial memory - $43 for 8gb ram
https://www.crucial.com/compatible-upgrade-for/dell/latitude-e6420

iFixit - Photos of the inside of the laptop:
https://www.ifixit.com/Device/Dell_Latitude_E6420

[entropy12]

Those are all good links, however I bought this used Dell Laptop for 80 bucks 5 years ago, and I refuse to invest any more money in it. It is now running fast enough for me.

And you don’t need even a Dell brand charger. The cheap clone charger from China working fine so far.

[daniel1212]

"Cost of upgrade from $43 ram memory to $60 for 500gb SSD or total $250 for 8gb ram and 1tb SSD and $10 external enclosure (may need 2)."

Getting a 500GB SSD (about $60) and cloning the OS to run off that would alone greatly increase speed. And thanks for helping him.