@Nyyerd I don't know whether adding your graphics chip to the database will change anything. The database was actually not updated at all for the 64-bit version, but something else changed, because now all AMD graphics cards are recognized, despite the fact that they're not listed in the original .sgr files. So I don't know whether the game even reads the files anymore—maybe it doesn't, maybe it does and there's an additional override somewhere. I did poke around a couple times looking for other files that might be serving the same purpose but didn't find anything useful.
At any rate, adding your chip is simple enough to do. The two files you would normally edit are graphicscards.sgr and graphicsrules.sgr, located within the game's package contents. It turns out though that you may only need to edit graphicscards.sgr, which makes things simpler. The full file path will start with either Applications or Users > your username > Applicaitons, and from there it goes like this:
The Sims 3.app > Contents > Resources > The Sims 3.app > Contents > Resources
To open an .app, right-click on it and select "Show Package Contents."
Before you do anything else, please right-click on graphicscards.sgr and select Copy, then right-click on your desktop and select Paste. This way, if the edit doesn't work, you can trash the copy you changed and put this one back, no harm done.
These instructions only apply to the original poster's graphics chip. If you'd like to get your card recognized, please create a new thread and ask for help.
Open graphicscards.sgr, use cmd-F to search for 8086, and you'll land here:
vendor "Intel" 0x8086
card 0x0042 "Havendale"
card 0x0046 "Havendale"
Below the line with "Intel" in it, create a new line and copy and paste this:
card 0x1927 "Iris Graphics 550"
Save, quit, launch the game, quit, and see whether your card is recognized. You should see a Found: 1 value in the deviceconfig.
If this doesn't work, let me know, and we can tweak the edits. Like I said though, the game may not care what's in this file at all.