Two things this will depend on - what are your system specs, and what games do you play.

If you’re on a mid/low end setup you’re not likely to be able to drive games at 4k, so go with the 1080p one. If you’re on a high end rig then 4k may make more sense.

Second thing is the games. If you mainly play esports titles that have low system requirements, you’ll be able to take advantage of more frames. If you play AAA/“cinematic” titles then 4k will be better.

Honestly though, my preference is 1440p at 120-144Hz. It’s a good sweet spot, just look for GSync support. Decent HDR is a bonus too.

I think diminishing returns make 240Hz not worth it for the average competitive player. There are 2 exceptions:

1. You're very competitive

2. You've got the money to spend

Here's one way to look at it 60Hz is 1 refresh every 17 milliseconds. At 165Hz it's every 6ms and at 240Hz it's every 4ms. So from that perspective whatever premium you're paying is to have the opponent's head appear on the screen 2ms faster (also impacted by other hardware induced delays). For context, the average person's response time to visual stimulus is about 250ms.

It's definitely nice to have and I haven't gone above 165Hz myself as a disclaimer but you will need to consistently hit 240 FPS in games to make use of the extra refresh rate and that requires a beefy CPU and/or GPU depending on the game. Especially if you want your 1% lows (FPS dips) to stay above 240 as well.

To my eyes, the main benefit of a higher refresh rate for fast paced games is the smoothness of motion (at least CSGO which is what I play). If I can track an enemy's head then I'm good and I don't think you need 240Hz for that.

Personally I would prefer higher pixel density and potentially better color accuracy and contrast, over 240hz.

If you have the card to push it you'd probably have a better experience with 1440p 165hz or 4k 140hz. Except at the highest levels of competition you're not really going to get much going to 240hz.

If you only play competitive games occasionally, I don't know if a 240hz monitor would be the best choice for you. Not that the 2546K is a bad monitor, but it sacrifices image quality for low response time and input lag.

A 1440p or 4k IPS monitor might be better, since image quality would be way higher. Additionally, a 4k one would have a longer life span, since a doubt 8k is going to be a viable thing in the near future.

But it will mainly depend on which you value (and game) more, response time or image quality.

There’s 3 factors you should take into account when trying to decide on resolution vs refresh rate:

• Your graphics card
• Your ideal monitor size
• How far you sit from the monitor

If you’re going for a bigger screen (e.g 32”+) and sit close to the monitor then you’re going to want a higher resolution (1440p+). If it’s a 24” like the BenQ and it’s a couple of feet away from you, you’re probably better off prioritising refresh rate.

I think this is a very personal decision. But if I were picking I would go with the 140Hz because that is a lot of frames already, and I'm very particular about having lots of pixels so that I can get crisp font rendering for code. In fact that is the exact choice I made for my monitor-before-last. But I haven't tried anything over 140Hz so I can't speak to the difference another 100Hz would make.

Personally would go with a higher resolution, especially if you're using it for more than gaming. I recently purchased a 4K/165Hz monitor that I'm enjoying. 1080p is claustrophobic for me when not gaming, but I've been on 1440p for awhile.