Do I need a new monitor?

I currently use a 23 inch monitor with a resolution of 1980 x 1080... I have been very happy with this display but have just upgraded from the 6D to the 5D4...
Would I benefit from a higher resolution monitor now I am dealing with 30mp images or does it make no difference?

Don - I think monitor choice is personal and kind of runs along the same line as 'do I need to upgrade my camera'. I think the best route to go is to ask yourself if your monitor is giving you satisfactory results. That said my previous workstation was a 2009 iMac with a resolution of (if my memory serves) 1920x1080. I upgraded to the iMac 5k and the difference is HUGE. I can see detail and perceive differences in sharpness where I couldn't before. Still, as fantastic as it is I don't consider the upgrade as being absolutely necessary. If you can pass by your local PC or Mac retailer with some of your images on a thumb drive and have a look at them. I think your own eyes will be the best judge.

It's all relative. If you view the full image on the monitor, the software determines what fraction of the full image resolution to 'throw away' in order to display it on the much smaller pixel matrix of your monitor.

Your 6D (5472 x 3648) image on 1920x1080 monitor throws away 65% of the image's horizontal resolution and 70% of the vertical resolution, and...

1. Your 5D4 (6,720 × 4,480 pixels) image on 1920x1080 monitor throws away 71.5% of the image's horizontal resolution and 76% of the vertical resolution
   
2. Your 5D4 image on 2560x1440 monitor throws away 62% of the image's horizontal resolution and 68% of the vertical resolution
   
3. Your 5D4 image on UHD1 monitor ( 3840 x 2160pixels) throws away 43% of the image's horizontal resolution and 52% of the vertical resolution
   
4. Your 5D4 image on true 4K monitor (4096 × 2160 pixels) throws away 39% of the image's horizontal resolution and 52% of the vertical resolution
   

I recently upgraded to the Dell 5K monitor, which I think is stunning, it's true 5K too at 5120×2880 pixels. it's the same display panel that is also used in the 5K iMac, but I'm running it with a Win 10 machine. Personally I think that MS have done a much better job of dealing with the screen magnification issue than Apple. Win 10 allows you to run at the full native resolution, but to magnify the scree up to about 300% which is far more flexible than Apple, who just offer running at 200% to simulate 2560×1440 resolution. I have no problems with running a relatively old version of MS Office, 2007, but I have had to upgrade from LR4/PSCS5 to the CC version, because Adobe decided to do their own window drawing, including title bars and menus etc, rather than use the system to do it, so that the scaling doesn't work. Everything else I use, RAWDigger, Fast RAW Viewer, DPP 4, Chrome and the previously mentioned Office 2007 all work fine. I accepted the need for the Adobe upgrade, and to be honest I don't have a camera that needs the latest version for support, but the improvements over the old versions are worth while. Anyone who is using a 5DIV and wants to process images in LR, without needing to use the DNG converter first, will need to be running the latest version anyway, so it is not likely to be a big problem moving to a higher resolution screen. The 5K monitor is 27" and running at 219 PPI it looks so much better than the 109 PPI of my friends 27" 2560×1440 109 PPI screen on his older iMac. That screen has supposedly the same colour gamut so it is a reasonably good comparison for just the resolution.

Alan

I don't think you specifically need to change your current larger just because you now have a higher resolution camera. It just means you'll have to scroll a bit more to check details at 100% than you did with the 6D. If your current display is old though and failing to profile accurately then a new upgrade is overdue. A larger display would probably be more comfortable to work with.