Here is a sample of the text with the "whiteness" around the font edges.

Not sure if you bought the units new, used, or refurb?

Heat can easily build up in an AIO with it being a PC and monitor in one.  Plus only 1 or 2 tiny fans to cool the whole thing   I've seen this have an effect on monitors.

They only other thing I can think of is to experiment with graphics options in Windows, but I truly think you ended up with 2 defective monitors on the AIO's in a row.

Purchased from Outlet.  While I understand heat build-up, these systems aren't that old (12th-gen CPU's), and I've got Dell AIO's that are 10 years old that still look great.

I have poked around Display Settings and everywhere else looking for some advanced display settings (in particular, sharpness) but did not find anything.

I even put in a new SSD and installed fresh Windows 10, and it still looks like junk.

2 bad AIO's with the same issue in a row?  Unlikely.  Lousy panel model using in the 5400? Most likely.  There may be others with different panel makers that look better, but the two I got look bad.

I am experiencing the same issue myself on five 5400 AIO desktops. Oddly, I got three 7400 AIO’s, which are supposed to have the same graphics and monitors. The only difference that I can see was some minor motherboard (usb) and memory up from 8 GB to 16 GB, the text looks perfect. 

I’m trying to decide what to do. Should I RMA the five I do have extended on-site warranty support. They are for use in business mainly for emailing, filling out, PDFs, and general business use. The actual graphics of a video or any type of image are excellent which makes me think it’s a driver issue that needs to be solved pretty quick. For general business use, they are worthless.

I feel for you.  One thing I didn't do was check Monitors under device manager and right click your monitor and choose Properties.  Then click the Details tab.  Now, drop down the Property chooser and select HardwareID's then look at the value.  each brand/model of panel has it's own unique value.  This will tell you if a particular panel is the issue.  If your 7400's have the same panel as the 5400's then it's probably BIOS or drivers that need fixing.  If the 7400 has a different panel (my guess that's the case) then Dell is using a lousy panels or panels that have defects on the 5400's.

Again, it seems like sharpness is turned way up, but there is not setting to adjust that, so hopefully it's just software.

Thanks I’ll check that to make sure.

I did pull up the specs for a service tag on the 5400 and 7400. Under the module for the panels, it shows the same designation. So then that would become a question of did they source them from two different vendors if they are the same. I’ve spent quite a few hours comparing the two different units. I also set up 10 of 5400s back in the summer of 2022 for another company, same specs, without this issue.

These were not purchased from the outlet store, which has me even more concerned because if they know they have a problem, they’re taking them back and then pushing them back out through the outlet store. 

So it looks like the monitor on the 5400 is a DEL94A, and on the 7400 it is a DEL940B. I am contacting support because the 5400s are mainly for Word, Excel, Adobe, and general business use-type things. Fuzzy text is a terrible user experience, and this either has to be addressed, or I have to send them back. Every one of the 5400s has the fuzzy (too sharp?) text of the 4 I installed. 

There is no mention on the specifications about the differences. Same chassis and same integrated GPU. I think I saw somewhere this happened before to a school and 200 units. Dell had to create a BIOS update to fix the sharpness issue with the fuzzy text.

Please share back here if you get it solved.  I'd like to buy 5400's again if there's a fix. I chose to return mine due to the fact I didn't think Dell would fix it before my return period.

It's definitely a problem that can hopefully be fixed with some sort of update. 

They are going to send someone out and replace the motherboards in all five units. Odd, because it seems to be a screen issue, unless the motherboard will somehow allow sharpness of output. They were very helpful in support chat. I am very appreciative of that. The units are specifically for workers to do nothing but create Word documents, PDFs, and read email. As I said earlier, it was quite odd because the video and any images are crystal clear with just the text being fuzzy.  

Same problem we have here in my compagny. Problem started out with the Optiplex 5400 with the Touch panel, and the AIO's without, didnt have the problem.

But the latest batch of around 46 AIO without touch, all have the samme fuzzy picture as the Touch Panels ones.

We've bought OP7400, touch and non-touch this time, because of the OP5400 model not being avaliable, and I really hope that the panels are of a better quality.