$4)$ Consider three different processors P$1,$ P$2,$ and P$3$ executing the same instruction set. P$1$ has a $4$ GHz

clock rate and a CPI of $2\mathrm{.}5.$ P$2$ has a $3$ GHz clock rate and a CPI of $1\mathrm{.}7.$ P$3$ has a $2\mathrm{.}5$ GHz clock rate and

has a CPI of $1\mathrm{.}0.(15$ marks$)$

a$.$ Which processor has the highest performance expressed in instructions per second?

b$.$ If the processors each execute a program in $20$ seconds, find the number of cycles and the number of

instructions.

c$.$ We are trying to reduce the execution time by $25\%$ but this leads to an increase of $10\%$ in the CPI. What

clock rate should we have to get this time reduction?

$5)$ Consider two different implementations of the same instruction set architecture. The instructions can be

divided into four classes according to their CPI $($class A$,$ B$,$ C$,$ and D$).$ P$1$ with a clock rate of $2\mathrm{.}5$ GHz and

CPIs of $1,2,3,$ and $3,$ and P$2$ with a clock rate of $3$ GHz and CPIs of $2,2,2,$ and $2.$ Given a program with a

dynamic instruction count of $2\mathrm{.}0$E$6$ instructions divided into classes as follows: $20\%$ class A$,10\%$ class B$,$

$40\%$ class C$,$ and $30\%$ class D$,$ which implementation is faster? $(15$ marks$)$

a$.$ What is the global CPI for each implementation?

b$.$ Find the clock cycles required in both cases?

$6)$ The Pentium $4$ Prescott processor, released in $2004,$ had a clock rate of $3\mathrm{.}6$ GHz and voltage of $1\mathrm{.}25$ V$.$

Assume that, on average, it consumed $15$ W of static power and $85$ W of dynamic power. The Core i$5$ Ivy

Bridge, released in $2012,$ had a clock rate of $3\mathrm{.}4$ GHz and voltage of $0\mathrm{.}9$ V$.$ Assume that, on average, it

consumed $35$ W of static power and $45$ W of dynamic power. $(20$ marks$)$

a$.$ For each processor find the average capacitive loads.

b$.$ Find the percentage of the total dissipated power comprised by static power and the ratio of static power

to dynamic power for each technology.

c$.$ If the total dissipated power is to be reduced by $15\%,$ how much should the voltage be reduced to

maintain the same leakage current? Note: power is defined as the product of voltage and current.