ONE 27in monitor @1440p or TWO 24in @1080p

Solution
Depends on what you are doing with the monitors. For gaming (depending on the game), the RX 480 is a little conservative (but will be good enough) for 1440p-resolution gameplay at good enough fps (again, depends on the game). For 1080p, it'll be a breeze no problem.

Now, I don't seem to understand your last question correctly. Are you asking if the RX 480 will be ok to run 3 monitors (a 27" 1440p and 23" 1080p monitors)? If that's the case, mixed resolution aside, then it'll run the 3 monitors just fine IF you are not gaming on ALL of them. But if you are going to do Eyefinity (not sure if it'll look great with differing reso's), then it'll definitely struggle a bit.
Depends on your current setup. I'd offer you my insights of the pros and cons and let you choose which would fit you best:

2x 24" 1080p PROS:
- You can do simultaneous programs in full screen (such as gaming on one screen and movie/web browser on another)
- The "windows' are physically segregated (by each monitors) which sometimes help in multi-tasking organization
- You'll probably game in just 1 monitor, so, a lower GPU requirement in running 1080p gaming
- Desktop fonts/sizes appear bigger (readable) in 1080p if monitors are distanced further away from where you sit

2x 24" 1080p CONS:
- Takes up more desk space (not ideal if you have a small desk that already includes space for your chassis, speakers, etc.)
- It's awkward to game in both screens having bezels/border in the middle
- Great chance you're head is always tilted one way or the other (depends on how you place the 2 monitors)
- Slightly angled monitor/s may produce uneven colors if TN panels are used (may be forced to get 2 IPS monitors)
- In your linked price, will cost more at $240 per monitor x 2 = $480.

1x 27" 1440p PROS:
- Takes less space in your desk / cleaner setup / less cable clutter
- Full front viewing / less strain in the neck and may opt for TN, VA, or IPS panels (wouldn't matter much due to direct viewing)
- Higher resolution offers more screen real estate and better quality especially when using certain programs or games
- Physically, a much larger screen size than the 24" (helps when viewing movies from afar, away from your desk).
- In your linked price, will cost less at ~$459.

1x 27" 1440p CONS:
- More taxing to run with your GPU due to more pixels compared to 1x 1080p (requires powerful/expensive GPUs)
- No pysical separation of windows as multi-tasking work will be via 1 screen (but will have more space due to higher res)
- When gaming on full screen, no other programs are visible
- Desktop icons/texts will appear smaller (need to increase font size or have to position monitor closer to be readable)
 


So i have a rx480, will it be ok to run a 27inch 1440p and a 23 inch 1080p monitors?
 
Depends on what you are doing with the monitors. For gaming (depending on the game), the RX 480 is a little conservative (but will be good enough) for 1440p-resolution gameplay at good enough fps (again, depends on the game). For 1080p, it'll be a breeze no problem.

Now, I don't seem to understand your last question correctly. Are you asking if the RX 480 will be ok to run 3 monitors (a 27" 1440p and 23" 1080p monitors)? If that's the case, mixed resolution aside, then it'll run the 3 monitors just fine IF you are not gaming on ALL of them. But if you are going to do Eyefinity (not sure if it'll look great with differing reso's), then it'll definitely struggle a bit.
 
Solution