My visual force page taking longer time to render or load the page if the records are more than 100. I am providing you with my VF page & controller class.
Please suggest do i have to use transient in order to overcome this.

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VF page: (for task):
<apex:pageBlock title="My Tasks" id="pb1" > <div class="slds-col--padded slds-size--1-of-1 myTaskList"> <apex:selectList value="{!selectedFilterTaskString}" styleClass="selectfld" size="1" onchange="filterTasks('{!JSENCODE(selectedFilterTaskString)}')"> <apex:selectOptions id="selectedOpt" value="{!filterTaskList}"/> <apex:actionFunction action="{!fetchRelatedTasks}" name="filterTasks" rerender="taskTabPanel,dataTableInitialization" status="spinnerStatus"> </apex:actionFunction> </apex:selectList> </div> <!-- List to iterate to be shown on page --> <apex:outputPanel id="taskTabPanel"> <div Class="slds-table slds-table--bordered"> <apex:pageBlockTable value="{!taskList}" var="task" styleClass="_dataTable">

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Controller:
public with sharing class EngTaskListPageCtrl {

public List<Task> taskList   {get;set;} //list of tasks to be shown on page
public List<SelectOption> filterTaskList {get;set;} //option list to be displayed in filter
public String selectedFilterTaskString { get; set;} //selected option from option list options
public Set<ID> BHGroupUserIDs{get; set;}//List of user ids belongs to Behavior Health User Group
private List<String> taskStatusList;

 public void fetchRelatedTasks(){
        try{
            String whereClause = ''; //creates where clause based on various criteria to be passed in Database query
            Id currentUser = UserInfo.getUserId(); //get current logged in user Id
             
            if (selectedFilterTaskString != 'MASCO BH'){
            if(selectedFilterTaskString == 'All Open (next 30 days)'){ 
                whereClause = 'WHERE (ActivityDate <= NEXT_N_DAYS:30) and';
            }
            else if(selectedFilterTaskString == 'Overdue'){ 
                whereClause = 'WHERE ActivityDate <= YESTERDAY and';
            }
            else if(selectedFilterTaskString == 'Today'){
                whereClause = 'WHERE ActivityDate = TODAY and';
            }
            else if(selectedFilterTaskString == 'Today + Overdue'){
                whereClause = 'WHERE ActivityDate <= TODAY and';
            }
            else if (selectedFilterTaskString == 'Tomorrow'){
                whereClause = 'WHERE ActivityDate = TOMORROW and';
            }
            else if (selectedFilterTaskString == 'Next 7 Days'){
                whereClause = 'WHERE ActivityDate = NEXT_WEEK and';
            }
            else if (selectedFilterTaskString == 'Next 7 Days + Overdue'){
                whereClause = 'WHERE (ActivityDate < TODAY OR ActivityDate = NEXT_WEEK) and';
            }
            else if (selectedFilterTaskString == 'This Month'){
                whereClause = 'WHERE ActivityDate = THIS_MONTH and';
            }
            
            //get the tasks based on criteria selected from page
            //DE109368-On Call Communication - Empty Task
            taskList = Database.query('SELECT id,Account.Name,Priority ,Status,WhatID, WhoID,Who.name,ActivityDate,Subject, What.Name,RecordType.Name, Description, '+
                                      'RelatedTo__c,RelatedTo__r.Name,Facility__c,Facility__r.Name,Clinical_Note_Subject_Type__c,type,CreatedDate FROM Task '+whereClause+' OwnerId =:currentUser '+
                                      'AND Status IN :taskStatusList LIMIT 1000');

            }
            //US1115209: Create a Post hospitalization queue for MASCO/OH - Devashri 
            else if (selectedFilterTaskString == 'MASCO BH'  && BHGroupUserIDs.contains(currentUser)){
              taskList.clear();
              List<Engagement__c> mascoEngList = Database.query('SELECT id FROM Engagement__c WHERE Market__c LIKE \'%Masco%\'');
              List<String> engIdList = new List<String>();
            for (Engagement__c eng :  mascoEngList) {
              engIdList.add(eng.Id);
            }
            
              taskList = Database.query('SELECT id,Account.Name,Priority ,Status,WhatID, WhoID,Who.name,ActivityDate,Subject, What.Name,RecordType.Name, Description, '+
                                      'RelatedTo__c,RelatedTo__r.Name,Facility__c,Facility__r.Name,Clinical_Note_Subject_Type__c,type,CreatedDate FROM Task WHERE WhatId IN :engIdList LIMIT 1000');        
            /*List<Task>taskToShows = new List<Task>();
            
            for (Task currentTask :  taskList) {
                if(String.isNotEmpty(currentTask.WhatID) && String.valueOf(currentTask.WhatID).startsWith('a1Y') 
                && engIdList.contains(currentTask.WhatID)){
                    if(Date.Today().daysBetween(currentTask.ActivityDate) <=0){
                      taskToShows.add(currentTask);
                    }    
                }   
            }
            
            taskList.clear();
            taskList.addAll(taskToShows);*/             
            }
            else{
              taskList.clear();
            }
        }
        catch(Exception ex){
            IsErrorOnLoad = true;
            ApexPages.addMessage(new ApexPages.Message(ApexPages.Severity.ERROR,ex.getMessage()));
            CustomLogger.log(ex,'',ApexPages.currentPage(),LoggingLevel.INFO);
        }
    }

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Thanks,
Anish Singh