Network interference?

Yeah, I know it isn't GPU or CPU intensive as I've monitored that. It's just that if I decide to take a quick break from the game (maybe to eat something) without closing the game and I use Alt-Tab and go to YouTube to continue watching a video I'd started, then the video playback gets slow. If I close the game and refresh the video's page it gets back to normal. However, (I later discovered) when I used the Steam overlay web browser (Shift-Tab) to view a video about the game, I didn't run into the same issue. Maybe it has to do with Chrome. I thought maybe for some reason the game was taking up network resources, but that doesn't make sense for a single player game. Perhaps something else is going on, but I don't recall having this issue with other games, which is why I find it really odd. I can continue to test it and see if I can figure it out or if it's worked itself out.

Thanks for the reply!

Off-topic, I really hope they remaster the other C&C/Red Alert games! 🙂

So, I just tested this again. With the game running (and sitting at the bonus content menu in order to be quiet) I Alt-Tab to continue to watch a video on YouTube that I have set for 1080p60 quality and it gets choppy, it's not even full screen. However, when I get back into the game and load the same video into Steam's overlay web browser (via Shift-Tab) with the same quality setting, the video runs perfectly normal. Perhaps it has to do with resolution scaling or recalibration as you suggested. My screen resolution is 1920X1200@60hz. I'm not sure what exactly is going on, but I now suspect (as I previously mentioned) that it has something to do with Chrome (as that is my default web browser that I am using on my desktop).

Thanks again for the reply!

Ok, I may have discovered what's wrong and how to fix it. I found the YouTube video skipping even when I wasn't playing the game. It was doing this even in MS Edge, in Chrome with all extensions disabled, after a reboot, and with my antivirus software temporarily disabled. This pretty much told me that it's not the game causing the issue. I tested the video out on another PC in the house on the same network and it was fine, so that seemed to tell me it had to do with my PC. I did a quick Google search (as I usually do when I run into a technical issue) and I found a video that showed that it's frame skipping. This is pretty much resolved by disabling hardware acceleration in Chrome's settings. It's still dropping some frames regardless of whether or not the game is running, but it's not noticeable. It may still be dropping a few frames in part because of the applications I have open like Libre Office, MSI Afterburner, Avast Antivirus, Chrome, and Steam. I believe Steam has a similar setting, which is probably why playback didn't suffer when watching a video via the Steam overlay web browser while playing the game. In case anyone else runs into this issue, I've included a link to the video below that will help show you how to eliminate at least most of the frame skipping. At first I thought this was the game's fault, because I hadn't experienced it before when playing other games, but I now doubt it's an issue pertaining to the game.

https://youtu.be/pvE618FXuho