My g5 plus can't even hold 4 apps in memory. Will this be fixed in Oreo or is there something which I can do to fix it. I had the stock messages, Gmail, chrome and hangouts open in the background. I only have Snapchat and a few games installed. I'm using Nova launcher and I have the 2gb model. This is frustrating as apps keep on refreshing.
Chrome is likely the big culprit here... Try a more RAM friendly browser and/or keep your number of Chrome tabs open to a minimum.
Not to be the bearer of bad news, but Nougat's memory management is quite good, and I don't think Oreo is much better from what I have heard... If anything Oreo uses a little bit more RAM. Leaps and bounds improvements have been made in Android's RAM management especially since the JellyBean era, I don't think there is much room for significant improvement especially since the base OS just keeps slowly getting bigger and bigger.
Try going into Developer Options and open Running Processes and see what is really using the RAM. To be honest, I just looked my biggest RAM users are Walmart and Sam's Club (which surprised me a bit, over 400MB between the two apps), Google, Facebook Lite, eBay, and Nova Launcher. Chrome wasn't even over 100MB on my device but I make sure to keep tabs closed (base Chrome is about 70-90MB, each tab is an additional 5-50MB per tab)