What is the difference between integrated and discrete graphics?
Integrated graphics share the main processor's silicon and the system's memory. Discrete graphics is a separate chip with its own dedicated memory.
Integrated (iGPU). Built into the CPU package. It uses system RAM rather than dedicated memory, drawing from the same pool as everything else.
Advantages: far lower power consumption and heat, which means longer battery life and thinner, quieter laptops; no additional cost; and entirely sufficient for the overwhelming majority of use — web browsing, video, office work, and even 4K video playback, which modern integrated graphics handle through dedicated hardware decoders.
Limitations: substantially lower 3D performance, and memory bandwidth is the fundamental constraint. Sharing system RAM with the CPU means competing for bandwidth that a dedicated card would not have to share.
Discrete (dGPU). A separate processor with its own VRAM, connected over PCIe.
Advantages: far higher performance for 3D rendering, gaming, video editing and effects, 3D modelling and machine learning workloads; dedicated high-bandwidth memory; and support for more displays at higher resolutions.
Costs: substantially more power and heat, shorter battery life, more weight and thickness, fan noise, and price.
What has changed the picture:
Integrated graphics improved considerably. Apple's unified memory architecture and AMD's recent integrated designs deliver performance that would have required a discrete card a few years ago, and the gap at the low end has largely closed. A cheap discrete GPU may not beat good integrated graphics.
Unified memory on Apple silicon changes the framing entirely — CPU and GPU share one high-bandwidth pool rather than the GPU borrowing slow system RAM.
Laptops frequently have both, switching automatically — integrated for ordinary work to save battery, discrete when demanded. This is why battery life varies so much by task, and why software occasionally uses the wrong one and needs forcing.
What to buy: integrated is right for most people. Choose discrete for gaming, 3D work, or sustained video rendering — and check the specific chip, since "has a graphics card" spans an enormous range.