yes

MIMD(Multiple Instruction streams, Multiple Data streams) multiprocessors fall into two classes Centralized Shared memory and distributed shared memory

Centralized Shared Memory Architecture has at most a few dozen microprocessors chips, that shares a single centralized memory. They have large caches, single memory, with multiple banks.

The single memory has a symmetric relation to all the processors and uniform access time from any processor.

Yes, dedicated memory is always better then shared (or integrated) edit answer after editing the question: but what is the shared memory option is much bigger than the dedicated option? (See edited question)

Advantages of shared memory are: 1) Less disk spaceis used because the shared momory code is not included in the executable program. 2) Less momory is used b'coz the shared memory code is only loadedonce.

dedicated memory is memory which is only connected to the GPU. changing shared memory to dedicated memory would involve rewiring the laptop, which would be far more expensive and far more effort than buying dozens of laptops with dedicated memory.