Syncing Processing to an Arduino that is Multiplexing - arduino

Question

I am sending 2 bytes from Processing to Arduino. These bytes are then stored in two values on the Arduino side, and then sent to a function that will then display them on a 7 segment 4 digit display.
The numbers are displayed fine! Yes, until about 5 seconds. I recorded it in slow motion.
9561 runs for about 5 seconds,
then a flash of 6100 very shortly,
and then 6195 very shortly
then it returns to 9561 for about 5 seconds again.
This can be changed slightly by altering the time each number is on the display, and I try to keep it below 4.
Anyways then changing the speeds on both programs also alters it, but I can't seem to get it right. Do I have to sync the programs through altering the speeds or is there a way to sync the numbers? I read into serialEvent() but not sure how to incorporate it into my project.
Here's my code below for the PROCESSING
void setup()
{
myPort = new Serial(this, Serial.list()[0], 9600);
}
void draw() {
seg[0] = 9;
seg[1] = 5;
seg[2] = 6;
seg[3] = 1;
int x = (seg[pos+1] & 0x000f)<<4|(seg[pos]) & 0x000f; //3210
int x2 = (seg[pos+3] & 0x000f)<<4|(seg[pos+2] & 0x000f);
myPort.write(x);
myPort.write(x2);
//0123
int disp1 = x;
int disp2 = (x & 0x00f0)>>4;
int disp3 = (x2 & 0x000f);
int disp4 = (x2 & 0x00f0)>>4;
//0123
print(disp1, '\n', disp2, '\n', disp3, '\n', disp4, '\n', '\n');
}
And ARDUINO
void setup() {
pinMode(GND1, OUTPUT);
pinMode(GND2, OUTPUT);
pinMode(GND3, OUTPUT);
pinMode(GND4, OUTPUT);
pinMode(aPin, OUTPUT);
pinMode(bPin, OUTPUT);
pinMode(cPin, OUTPUT);
pinMode(dPin, OUTPUT);
pinMode(ePin, OUTPUT);
pinMode(fPin, OUTPUT);
pinMode(gPin, OUTPUT);
pinMode(light, OUTPUT);
Serial.begin(9600);
}
void digitdisplay(byte x,byte x2)
{
//unsigned char tn = int (num/1000);
//if (tn>10)
//{
// tn = tn - 10;
//}
//
//unsigned char hn = int (num/100)%10;
//unsigned char tenn = int (num/10)%10;
//unsigned char on = int (num%10);
int disp[4];
disp[0] = ( x & 0x000f);
disp[1] = ( x & 0x00f0)>>4;
disp[2] = ( x2 & 0x000f);
disp[3] = ( x2 & 0x00f0)>>4;
numberselect(disp[0]);
digitselect(1);
delay(t);
numberselect(disp[1]);
digitselect(2);
delay(t);
numberselect(disp[2]);
digitselect(3);
delay(t);
numberselect(disp[3]);
digitselect(4);
delay(t);
}
void loop()
{
int x,x2;
if (Serial.available()>0)
{ // If data is available to read,
x=Serial.read();
x2=Serial.read();
}
//shiftlight(maxrange);
digitdisplay(x,x2);
}