Intermittent problem on form refreshed, upon entered data for @lookup

I have these Keyfields, which upon enter, and press F9 should fill in other data in other fields, since they are using this field as lookup value for other fields.

the problem is that, sometime it takes more than 2 minutes for these data to be filled in, sometime, only few seconds. How do I troubleshoot such problem?

or could it be my database, which is 13 GB currently? or my Operating System, or harddisk having missing FAT data whatsoever?

any help is greatly appreciated.

Subject: Intermittent problem on form refreshed, upon entered data for @lookup

The access time for a view may vary when the view needs a refresh, and in large db’s this can take some time.