Graphic artefacts after I updated mavericks on 19.0.5. The same on Yosemite 10.10.3

[oZen]

Hi everyone.

 

I've built a hack last summer. Approx:

 

- Gigabyte Z87 based (the same everyone bought at this moment) with 4770k core i7 on it.

- MSI GTX 770 based graphic card.

 

- Clover 3202, very basic options, UEFI startup, NO DSDT.

 

 

Everything went just fine out of the box since I update Mavericks in 10.9.5

After this I had those graphic artefacts in youtube, in basic software like preview, or even on the finder with the icons of movies (those little previews you can click on).

 

I though that installing Yosemite could resolve my issue. But I was wrong. Sadly it's the same... (Probably the same graphic driver on 10.9.5 and 10.10.3)

 

I also tried to install the latest Nvidia web drivers: same result...

 

Note that if I launch a first time a youtube video for example it's gonna be buggy, full of artefacts, but if I reload the page it turns back to normal and I can see the video. Kind of a buffer issue or something...

 

To finish I notice that recent post describing something close but before the complete start of the system:

http://www.insanelymac.com/forum/topic/306254-graphic-artifacts-on-startup/

 

I'm gonna give a try with the built in HD 4600 graphics to compare.

 

Here are the artefacts:

 

Thanks a lot in advance !