i5 4440 vs i5 4590?

Yes, same socket.

The 4590 will perform slightly better in terms of FPS in games, as it is clocked at 3.3 GHz. The 4440 is clocked at 3.1 GHz, so it runs a bit slower. If you can get them at a similar price get the 4590.
 
Yes, you will probably need new RAM if moving to a Skylake build.

Unless your current DDR3 ram is designated with an 'L' at the end (for low voltage) you'll need to upgrade your RAM as well when moving to the i5-6500.

@ rolli59, deja vu 😉
 


I am probably going to go with the i5 4590 just due to the fact that ddr4 memory is way out of my budget. -cpu and mobo fine just + ram as well too much. Is it worth to go with the i5 4590 or save up for skylake. I mean after those 2 purchases i doubt i am ever going to buy/upgrade my pc again