Welcome to my blog about Intel(R) Active Management Technology. The question below was posted on the vPro Expert Center.
Special Thanks to Vitaly Lubart, Senior SW/FW Engineer at Intel, for answering this question.
This is an expected behavior for the Intel AMT KVM remote control feature when working in some BIOSes, as well as DOS . It is caused by an integrated Gfx HW limitation of the KVM feature that is needed for showing the User Consent Sprite while the display is in VGA mode. When the display is in VGA mode the display image cannot be shown along with the Sprite so when the Sprite User Periodic Notification is being shown, the screen itself cannot be displayed.
For this reason the Sprite User Periodic Notification is done once in about 10 sec (instead of 3 sec for non-VGA mode).