[PIC] LCD display slows down processing in proteus.experts opinion required

unsigned int adc_data[4];
unsigned char analog_selected = 0;
unsigned char str[50];
unsigned short duty1=255;
float form1;
// LCD Module connections
sbit LCD_RS at RD0_bit;
sbit LCD_EN at RD1_bit;
sbit LCD_D7 at RD7_bit;
sbit LCD_D6 at RD6_bit;
sbit LCD_D5 at RD3_bit;
sbit LCD_D4 at RD2_bit;
// End LCD module connections

// LCD Pin direction
sbit LCD_RS_Direction at TRISD0_bit;
sbit LCD_EN_Direction at TRISD1_bit;
sbit LCD_D7_Direction at TRISD7_bit;
sbit LCD_D6_Direction at TRISD6_bit;
sbit LCD_D5_Direction at TRISD3_bit;
sbit LCD_D4_Direction at TRISD2_bit;
// End of LCD Pin direction
void interrupt(){
  if (PIR1.ADIF) {
    PIR1.ADIF=0; // clear AD interrupt flag
    switch (analog_selected){
      case 0:
        adc_data[0] = (ADRESH << 8) | ADRESL; // read dadta from channel 0
        analog_selected++; // increase channel index
        ADCON0 = 0b11001001; // select channel 1
        break;
      case 1:
        adc_data[1] = (ADRESH << 8) | ADRESL; // read dadta from channel 1
        analog_selected++; // increase channel index
        ADCON0 = 0b11010001; // select channel 2;
        break;
      case 2:
        adc_data[2] = (ADRESH << 8) | ADRESL; // read dadta from channel 2
        analog_selected++; // increase channel index
        ADCON0 = 0b11011001; // select channel 3;
        break;
      case 3:
        adc_data[3] = (ADRESH << 8) | ADRESL; // read dadta from channel 3
        analog_selected = 0; // return channel 0
        ADCON0 = 0b11000001; // select channel 0;
        break;
    }
    Delay_Cyc(3); //wait acquisition time
    ADCON0.F2=1; //start conversion again
  }
}
                              // Loop variable

void main(){
  unsigned int i=0;
  float temp;
  CMCON = 7; //Disable ADC  Comparators
  TRISA=0xFF;
  TRISB=0;
  TRISC=0;
  TRISD=0;
  TRISE=0;
  ADCON1 = 0x82; // AN0->AN4 selected as analog input  1/FRC 0010 for AN0 to AN4
  ADCON0 = 0b11000001; // Configue analog mode
  INTCON.GIE = 1; //Enable global interrupt
  INTCON.PEIE = 1; //Enable peripheral interrupt
  PIE1.ADIE = 1; //Enable ADC interrupt
  Delay_us(20); //wait for acquisition time
  ADCON0.F2 = 1; //start conversion
   //PORTE.F0=0;
  //PORTE.F1=1;
  CCP2CON=  0x0B;       //wait for AD conversion and reset timer
  Lcd_Init();
  Lcd_Cmd(_LCD_CURSOR_OFF);
  PWM2_Init(25000); // Initialize PWM1 for 25Khz
               PWM2_Start(); // start PWM1
               PWM2_Set_Duty(duty1); // Set current duty for PWM1
                while(1)
               {

    temp = adc_data[i]; // read data from channel i
    //Delay_us(20); //wait for acquisition time
      i=0;
      form1=((temp*5)/1023) ;
    //PORTD = form1; // Send lower 8 bits to PORTD
    //PORTC = temp >> 2; // Send 2 most significant bits to RB7, RB6
   //form1=((temp*5*10)/(1023));  //i divided buck output by 10 and gave it to AN0
   FloattoStr(form1,str);
    Lcd_Cmd(_LCD_CLEAR);
    Lcd_Out(1, 1, "Battery Voltage=");
    Lcd_Out(2, 1, str);
    //Delay_ms(10);
    duty1-=2.55;
   PWM2_Set_Duty(duty1);
   }
}