HP Vectra XU5 Reference Manual page 30

Graphics/Integrated Video
According to model, the video subsystem is composed of an Vision864 Graphical User
Interface (GUI) accelerator for the PCI bus, a 64-bit true color RAMDAC and DRAM array, or
it may have a Matrox Video Board. Refer to the documentation supplied with your Matrox
Board.
The highest mode that is supported is 1280 x 1024 with a screen refresh rate of 75 Hz.
Vectra XU Technical Reference System Overview 30