View Full Version : UEFI BIOS and CRT monitor

10-06-2012, 03:39 AM
There is a problem with UEFI BIOS on P8Z68-V LX motherboard when used with analog (DSUB) output. The BIOS sets wrong resolution - 640x480 instead of 1024x768, though the monitor is capable of the resolution. Generally the BIOS works, I can change settings, save them, update BIOS etc. However the bios has artifacts and some options donít fit in 640x480 and are below, off-screen.

The bug is on iGPU graphics (HD2000), Gigabyte Radeon HD5570, Sapphire HD7850.
One exception for me was the HD5570 modded with ASUS HD5670 BIOS, then the motherboad BIOS was displayed properly:


Hereís how it looks on monitor.
Good settings:
post 800x600

bios 1024x768

Bad settings:
post 640x480

bios 640x480

I found a quite easy workaround for this:
- power on the computer with monitor switched off
- keep pressing the Delete key for about 10 seconds
- switch the monitor on
then the BIOS sets proper graphic mode. But still, a fixed bios would be better.

A few examples of the same error from the web:
Asus P67 Pro: UEFI screen cut-off - [H]ard|Forum (http://hardforum.com/showthread.php?t=1612128) (P8P67)
EFI bios all I can see is the upper left corner? - Chipsets-Bios - Motherboards-Memory (http://www.tomshardware.co.uk/forum/290777-12-bios-upper-left-corner) (P67)
ASUSTeK Computer Inc.-Forum- UEFI BIOS setup menu is displaying at wrong resolution (http://vip.asus.com/forum/view.aspx?id=20110917055821023&board_id=1&model=P8Z68-V+PRO&page=1&SLanguage=en-us) (P8Z68)

So far the bug sneaked through all P8Z68-V LX BIOS versions Ė including current 4001.
I hope that ASUS will be interested to make the UEFI BIOS more reliable (working on CRT monitors too) and release fixed BIOSes for P8Z68-V LX and similar motherboards.

10-06-2012, 11:30 PM
Actually the thing is not many people uses CRT monitor nowadays so support for CRT monitor is neglected part. The Dsub is mainly there to support old projectors.

10-07-2012, 04:38 AM
it isn't limited to CRT, had the same issues with a 17" tft using dsub (cause its all it has)

10-10-2012, 02:24 PM
^^ That sucks. :-(