A Solid State Disk (SSD) is a type of Hard Disk. It is different than the traditional Hard Disk Drives because it is not a spinning disk. It is considered a much safer alternative to a hard disk because there are less losses associated with it. There is no moving disk, so it does not create heat, which would mean the user doesn't necessarily have to worry about the SSD overheating and crashing. It is also preferable because it is quieter since there is no spinning disk making noise.
A Quad Core is more preferable over a Dual core because it would be double the space. The core is where the computer "reads" the instructions for its processes. A Quad Core has the equivalent of 4 single cores, while a Dual Core has the equivalent of 2 cores. The more cores a computer is operating with, the faster it can operate.