Monitor advice needed

[ste91]

Currently using a TV but am looking to upgrade to a proper monitor soon, but the amount of choice is a bit confusing, resolution, refresh rate, sync, etc... I'm really not sure what to go for.

I've got an RX580 and the box hasn't been opened yet so I do have the option of selling it and upgrading to a 1070 but I'm not sure if it's worth the extra cost, the RX580 seems capable enough at 1080@144hz or 1440@60hz on most games depending on the settings and since I'm only on a 720p@60hz TV at the moment either of those would be an improvement.

I mainly play a mix of FPS and RPG games with the odd strategy game as well, so I'm leaning more towards 1080p@144hz.

I've watched a few videos on it but I still don't fully understand Freesync, in simple terms does Freesync just smooth out the refresh rate i.e. if the game is running at around 100FPS on a 144hz monitor and then drops to 70FPS occasionally does Freesync just smooth things out so that your don't notice the drop in frame rate? Whereas if you were using V-Sync and the frame rate dropped you'd be able to notice it?

Also what size monitor should I be looking for is there a recommended size for each resolution? 24" for 1080 seems popular.

 

[ste91]

After looking at the extra cost of a 1070 and the cheapest G sync monitors being around £400 I've decided to keep the RX580, since it can run 1080@144 or 1440@60, and there are a few Freesync monitors in the £250-£300 price range that suit both of those settings.

So for FPS/RPG games with the occasional strategy game would I be better off with a faster refresh rate or a higher resolution?
Am I right that 1080@144hz is the better "long term" option as I can keep running newer games at 1080p but with a slightly lower but still resaonable frame rate whereas new games in a few years might require settings turned down to maintain 1440@60?