Does this happen immediately upon starting the computer or when it seemingly is attempting to go into windows (after post)? I ask because I am not aware of when the MSI screen comes up.
I've had two occassions when this particular issue happened to me - once when the videomemory on my graphics card went bad and the other time when the northbridge on a motherboard went bad.
If this part of the post is the only time you notice this problem and its brief I would disable the logo screen and see if you still have problems after XP loads.
Stress the 1600 with 3Dmark 2006 or check for artifacts with ATI tool.
Remember that the ATI drivers are not even loaded until late into the boot up in the windows environment.
If this happens under all conditions then I would agree that the card may be defective.
Otherwise the brief glitch may just be a spike from that power hungry card during initialization.
It's immediately as you power on the computer. I'm guessing this screen is some replacement put in by MSI for the POST screen you would normally see.
I'll give atitool and 3dmark a shot.