Randomly in the latest snapshots for 1.5 I have been getting one or more of the following happening while playing/testing:

1) Visual distortions. See Screenshot, this is one example of the type of distortion. Another I have seen are black "lines" or vertices shooting up around the map.

2) Lag (either in game only or my entire windows system)

When the lag occurs on Windows there is a quick flash of black on both my montiors then the mouse cursor jumps/lags, the audio stutters, etc. Windows goes back to normaly only when I end the process for Java.

Alternatively, when the black flash occurs, Minecraft seems to "recover", but I will see visual distortions in the textures (again see screenshot).

I removed older Java versions and updated to Java 7 Update 11 and force updated minecraft.

If I go back into Minecraft using the snapshot after killing java.exe it automatically lags at the Mojang screen. It takes up to 10 seconds before getting to the main menu. Java seems to be hovering at around 260MB of memory (as per the TaskMan). I have to terminate Java again. I then immediately loaded 1.4.7, Minecraft runs normal for hours.

After searching the bug reports I see others have white or other texture issues and some have lag issues. I didn't see any reference to Windows lagging or this type of texture issue. I first seen this in 13w03a and happens in 13w03b as well.