Teletext like filckering problem on Geforce 9600M GS with nvidia 190.42

[nusch]

After a bit of hours developing under KDE the screen starts to flicker, especially the fonts, see how the clock, menus and filenames looks in screenshots.
In dmesg I've seen:

[95820.760107] NVRM: Xid (0001:00): 8, Channel 00000003
[97889.315043] npviewer.bin[11734]: segfault at ff999ed8 ip 00000000ff999ed8 sp 00000000ffa57dac error 14
[100125.335986] NVRM: Xid (0001:00): 13, 0001 00000000 0000502d 00000100 00000000 00000001
[100564.836288] NVRM: Xid (0001:00): 13, 0001 00000000 0000502d 00000100 00000000 00000001
[102403.867665] NVRM: Xid (0001:00): 13, 0001 00000000 00005097 000015e0 00000000 00000040
[102644.864138] NVRM: Xid (0001:00): 13, 0001 00000000 00005097 00000538 3f1f9fa0 00000040
[102938.868673] NVRM: Xid (0001:00): 13, 0001 00000000 00005097 0000194c 00000000 00000080
[103099.367513] NVRM: Xid (0001:00): 13, 0001 00000000 0000502d 00000100 00000000 00000001
[104395.765176] NVRM: Xid (0001:00): 13, 0001 00000000 00005097 00000538 3f800000 00000040

The temperature reported from nvidia-settings was 62C and after restarting computer everything started to work like previously so I reject overheating problem. But this always happens after some time when computer is turned on. This problem with flickering only texts I experienced first time, but often I got whole screen flickering in manner that it was imposible to restart computer. In such situation I had seen only changing graphics - when I clicked somewhere some part of screen changed but not the one I clicked, and some buffered icons of applications were displayed in place they shouldn't.

Included nvidia-bug-report.log.gz was generated after the restart so in case any information about state of card at the time of failure is aquired it wouldn't be suitable.