A CPU has five stages pipeline and runs at $$1$$ $$GHz$$ frequency. Instruction fetch happens in the first stage of the pipeline. A conditional branch instruction computes the target address and evaluates the condition in the third stage of the pipeline. The processor stops fetching new instruction following a conditional branch until the branch outcome is known. A program executes $${10^9}$$ instructions out of which $$20$$% are conditional branches. If each instruction takes one cycle to complete on average, then total execution time of the program is

A $$5$$ stage pipelined $$CPU$$ has the following sequence of stages $$IF$$-Instruction fetch from instruction memory, $$RD$$-Instruction decode and register read, $$EX$$-Execute: $$ALU$$ operation for data and address computation, $$MA$$-Data memory access-for write access the register read and $$RD$$ stage it used, $$WB$$-Register write back.

Consider the following sequence of instructions:
$$\eqalign{ & {{\rm I}_1}:L\,R0,\,\,Loc1;\,R0 < \,\, = M\,[Loc1] \cr & {{\rm I}_2}:A\,R0,\,R0;\,\,\,\,\,\,R0 < \,\, = R0 + R0 \cr & {{\rm I}_3}:A\,R2,\,R0;\,\,\,\,\,\,R2 < \,\, = R2 - R0 \cr} $$

Let each stage takes one clock cycle.
What is the number of clock cycles taken to complete the above sequence of instructions starting from the fetch of $${{\rm I}_1}?$$

A $$4$$-stage pipeline has the stage delays as $$150, 120,160$$ and $$140$$ nano seconds respectively. Registers that are used between the stages have a delay of $$5$$ nanoseconds each. Assuming constant clocking rate, the total time taken to process $$1000$$ data items on this pipeline will be

The performance of a pipelined processor suffers if