Sorry, but the generation number isn't part of the performance ratings that the old graphics solutions such as yours included in the names. This is the Simcity 2013 forum. If that is not your game, you are off topic.
Simcity 2013 Requirements
Operating Systems:
SimCity will run on Windows XP, Vista, and Windows 7.
CPU:
Intel C2D E4400, 2 GHz, or AMD X2 4000
Video Card:
Geforce 7800 GT or Radeon HD 2600 XT with 512 MB VRAM
***NOTE: each of the above-mentioned must also have Shader 3.0 or better support, and it is essential to the game’s performance and stability that the latest possible drivers for your video card are installed at all times (see my note#).
2 GBs RAM
Direct3D Dx9
Needed space on HDD 10 GB
Optical Drive:
DVD-ROM drive required.
Internet Connection:
Players will need an Internet connection of at least 256 kbps download and 64kbps upload or faster.
Here's that Note# :
The equivalent to those minimums they named for playable results today: Geforce GT 640 and Radeon HD 6570.
Since cards' names are practically meaningless without a score sheet, the Geforce 205, 210, 215, 305, 310, 315, 430, 510, 515, 520, 610, 615, and 620 are all below the Geforce 640. The GT 630 is a fence-sitter, not recommended (to be fully complete, all of the Geforce 6n00s, any 7600 - downward, 8500 -downward, 9400-downward, are below minimum). The Radeon X1550, HD 2400, HD 3450, HD 3470, HD 4350, HD 4550, and HD 5450 are all below the 6570. The HD 6450 may be a fence sitter, however, I don't believe it is actually quite that good. The HP card that Hewlett Packard sold as an HD "7450" was just a 6450 all over again, and there will be an OEM-only "8450" that is still the same, just renamed.
This game's minimum is not an "HD 2400" of any nature, it is an HD 2600 XT.
If "cards' names are practically meaningless without a score sheet", why determine suitability of cards by name? Nevertheless, I have a Radeon Pro Vega 56 8176 MB, which appears to exceed (by name) the Radeon HD 6570 you state as the current minimum; yet I still get the same error message.
Certainly the newer cards will meet or exceed requirements for the graphic needs of SimCity. The error message you're getting is probably just pointing to an issue with the game's interaction with your graphics settings or card, if you're lucky - sort of a default for graphic issues when it has nothing specific from which to draw.
A few things to keep in mind with SimCity - remember, this is a legacy game, programmed in 2013 with no updates since 2015. It does not play well with dual monitors or 4k monitors. Lower your resolution settings, and disable any dual monitor capabilities while playing SimCity. Is this on Mac OS? Make sure you upgrade to Mojave; the last few Mac updates broke SimCity for Mac users. There was a problem with Radeon drivers a year or two ago, so make sure your drivers are updated to the newest available. Double-check that SimCity.exe and Origin.exe are both added to your firewall and anti-virus exception lists.
You can also try to repair the game - in Origin, right-click the SimCity icon and choose "Repair".
If none of these general tips help, reply back with more info - what OS (Mac version, Windows 8/10?), can you click through the error and still play the game? Have you successfully played SimCity before?
