In Harvard architecture, the CPU is connected with both the data memory (RAM) and program memory (ROM), separately. In Von-Neumann architecture, there is no separate data and program memory. Speed of execution is faster because the processor fetches data and instructions simultaneously.

1. HARVARD & VON-NEUMANN
ARCHITECTURE

2. What is
Harvard
Architecture ?
The Harvard architecture is a
term for a computer system
that contains two separate
areas for commands or
instructions and data.
The CPU fetched the next
instruction and loaded or
stored data simultaneously and
independently.

3. What is Von-Neumann
Architecture ?
A von Neumann architecture machine,
designed by physicist and
mathematician John von Neumann
(1903–1957) is a theoretical design for a
stored program computer that serves as
the basis for almost all modern
computers.

4. HARVARD ARCHITECTURE
Based on the Computer model
which employed separate buses for
data and instructions.
Has separate memory space for
instructions and data, which
physically separate signals and
storage for code and data memory,
which in turn makes it possible to
access each of the memory system
simultaneously.
VON-NEUMANN ARCHITECTURE
Design based on the concept of
stored-program where programs
and data are stored in the same
memory.
 Has only one bus that is used for
both instruction fetches and data
transfers, and the operations must
be scheduled because they cannot
be performed at the same time.

5. HARVARD ARCHITECTURE
The Processing Unit(PU) can
complete an Instruction in one
cycle if appropriate pipelining
strategies are in place.
Cost is much higher because of the
Complex Architecture that
employs two buses for instructions
and data.
VON-NEUMANN ARCHITECTURE
PU need two clock cycles to
complete an Instruction.The
processor fetches the Instruction
from memory in the first cycle and
decodes it, and then the data is
taken from memory in the second
cycle.
Cost is much lower

6. HARVARD ARCHITECTURE
Harvard architecture is a fairly
new concept used primarily in
microcontrollers and digital
signal processing (DSP).
VON-NEUMANN ARCHITECTURE
Von Neumann architecture is
mainly used in every machine
you see from desktop
computers and notebooks to
high performance computers
and workstations.

7. Summary of Von Neumann vs. Harvard
Architecture
Von Neumann architecture is like the Harvard architecture except it
uses a single bus to perform both instruction fetches and data
transfers, so the operations must be scheduled whileThe Harvard
architecture, on the other hand, uses two separate memory
addresses for data and instructions, which makes it possible to feed
data into both the busses at the same time.
The complex architecture only adds to the development cost of the
control unit against the lower development cost of the less complex
Von Neumann architecture which employs a single unified cache.