Along with a microprocessor that serves as a PC's core calculating engine, Spider includes graphics technology for serving up the advanced graphics beloved by gamers and a chipset that ties those elements together and connects them to other resources such as the main memory.
Digital Foundry put together this comparison video of the Unreal 4 Engine working on PS4 and PC, concluding that the PC version still looks better, though adding that it could be due to the relative youth of the PS4 by comparison.