## 3 Performance Implication of NVM Based Storage
### Implications of Alternative PC Configurations
The memory power consumption \(P_{DRAM}\) is calculated as  
\[P_{DRAM}=P_{DRAM\_static}+P_{DRAM\_active} \tag{1}\]  
where  
\[P_{DRAM\_static}=Unit\_static\_power\ (\text{W/GB})\times Memory\_size\ (\text{GB})\ \text{and,}\] \[P_{DRAM\_active}=Read\_energy_{DRAM}\ (\text{$0$})\times Read\_freq _{DRAM}\ (\text{$\text{$\text{$\text{$\text{$\text{$\text{$\text{$\text{$\text{$ $\text{$\text{$\text{$\text{$\text{$\$}$}$}$}$}}}}}}$}})+Write\_energy_{DRAM}\ (\text{$0$})\times Write\_freq _{DRAM}\ (\text{$0$})\times Write\_freq _{DRAM}\ (\text{$0$})\).  
\(Unit\_static\_power\) is the static power per capacity including both leakage power and refresh power, and \(Read\_energy_{DRAM}\) and \(Write\_energy_{DRAM}\) refer to the energy required for read and write operations for the unit size, respectively. \(Read\_freq_{DRAM}\) and \(Write\_freq_{DRAM}\) are the frequencies of read and write operations for the unit time, respectively.  
The NVM power consumption \(P_{NVM}\) is calculated as  
\[P_{NVM}=P_{NVM\_idle}+P_{NVM\_active} \tag{2}\]  
where  
\[P_{NVM\_idle}=Idle\_rate_{NVM}\times Idle\_power_{NVM}\ (\text{W})\ \text{and,}\] \[P_{NVM\_active}=Read\_energy_{NVM}\ (\text{$0$})\times Read\_freq _{NVM}\ (\text{$\text{$\text{$\text{$\text{$\text{$\text{$\text{$\text{$\text{$ $\text{$\text{$\text{$\text{$\text{$\text{$\text{$\text{$ $}}}}$}$}$}}}}}}})+Write\_energy_{NVM}\ (\text{$0$})\times Write\_freq _{NVM}\ (\text{$0$})\times Write\_freq _{NVM}\ (\text{$0$})\).  
\(Idle\_rate_{NVM}\) is the percentage of time that no read or write occurs on NVM and \(Idle\_power_{NVM}\) is the power consumed in NVM during idle time. \(Read\_energy_{NVM}\) and \(Write\_energy_{NVM}\) refer to the energy required for read and write operations for the unit size, respectively. \(Read\_freq_{NVM}\) and \(Write\_freq_{NVM}\) are the frequencies of read and write operations for the unit time, respectively.  
The HDD power consumption \(P_{HDD}\) is calculated as  
\[P_{HDD}=P_{HDD\_idle}+P_{HDD\_active}+P_{HDD\_standby} \tag{3}\]  
where  
\[P_{HDD\_idle}=Idle\_rate_{HDD}\times Idle\_power_{HDD}\ (\text{W}),\] \[P_{HDD\_active}=Active\_rate_{HDD}\ \times Active\_power_{HDD}\ (\text{W}),\] \[P_{HDD\_standby}=Transition\_freq _{HDD}\ (\text{$0$})\times(Spin\_down\_energy_{HDD}\ (\text{$0$})+Spin\_up\_energy_{HDD}\ (\text{$0$})).\]  
\begin{table}
\begin{tabular}{c c c c} \hline
**Component** & **16 GB DRAM + NVM PC** & **64 GB DRAM + HDD PC** & **Note** \\ \hline CPU & Figure 12:056  (3)} & (2) ASRC H110M-HDS R3.0 \\  & & & & Micro AITX LGA1151 & Motherboard \\  & & & & (3) ASRC B250 & \(\text{P}\)4 TX \\  & & & & LGA1151 & Motherboard \\ \hline DRAM & Figure 12:1370  (7)} & (6) Intel Optane 900P (280 GB) \\  & & & & (7) Seagate Barracuda Compute \\  & & & & HDD 2 TB \\ \hline \multirow{4}{*}{ \begin{tabular}{c} Misc \\ (CPU Cooler, Case, \\ Power) \\ \end{tabular}  } & \multirow{4}{*}{\$156} & \multirow{4}{*}{\$156} & \multirow{4}{*}{\$156} \\  & & & \\ \cline{1-1} \cline{4-1 Idle_rate\({}_{HDD}\) is the percentage of time that no read or write occurs on HDD and Idle_power\({}_{HDD}\) is the power consumed in HDD during idle states. _Active_rate\({}_{HDD}\)_ and _Active_power\({}_{HDD}\)_ refer to the percentage of time that read or write occurs on HDD and the power consumed in HDD during active states, respectively. _Transition_freq\({}_{HDD}\)_ is the frequency of state transitions between idle and standby states for the unit time. _Spin_down_energy\({}_{HDD}\)_ and _Spin_up_energy\({}_{HDD}\)_ refer to the energy required for spin_down and spin_up operations, respectively. The static power is consumed consistently in DRAM regardless of any operations as DRAM memory cells store data in small capacitors that lose their charge over time and must be refreshed. As the size of DRAM increases, this static power keeps increasing to sustain refresh cycles to retain its data. However, this is not required in NVM because of its non-volatile characteristics.