1GB GPU may or may not be good for gaming. Actually, this depends on the minimum and recommended system requirements of the game you’ll be playing. You have to check out the website or packaging of your game to ensure you have the right GPU for the job.
For instance, Fortnite has a recommended video card of NVIDIA GeForce GTX 660 or AMD Radeon HD 7870 or equivalent DX11 GPU. This means the recommended VRAM for the game is about 2GB. On the other hand, The Elder Scrolls Skyrim: V has a recommended video card of NVIDIA GeForce GTX 260 or its AMD Radeon 4890 equivalent, meaning it is suggested to use a graphics card of about 1GB in memory.