screen interference since upgrading to OSX 10.9, MacBook Pro

Hmmn, try making sure your resolution is set correctly and the colour scheme is set correctly too in the displays section of system preferences.

If that doesn't work I'd take it to an apple store for them to have a look at if I were you !

You have the MacBookPro6,2, the Edsel of Macs. It may be covered by this program:

MacBook Pro (15-inch, Mid 2010): Intermittent black screen or loss of video

Make a "Genius" appointment at an Apple Store, or go to another authorized service provider, to have the machine tested. The routine hardware diagnostics used by service providers may not detect the fault. There is a specific test for this issue.

Print the support page linked above and bring it with you.

Note that the replacement program only applies within three years of purchase. If you wait beyond that date, Apple may refuse the service. In that case, you'll be quoted a price of about $300 (in the U.S.) for a depot repair. The model was discontinued in February 2011, so the replacement program will be ending quite soon.

Back up all data on the internal drive(s) before you hand over your computer to anyone. If privacy is a concern, erase the data partition(s) with the option to write zeros* (do this only if you have at least two complete, independent backups, and you know how to restore to an empty drive from any of them.) Don’t erase the recovery partition, if present.

*An SSD doesn't need to be zeroed.

The problem is the Automatic Graphics Switching. (As posted in Frank23456: https://discussions.apple.com/thread/5493333?answerId=24085505022#24085505022&ac_cid=tw123456#24085505)

Head over to your System Preferences > Energy Saver, and unselect "Automatic graphics Switching". I find when I toggle that it will solve the problem.

It's not a permanent fix, but it clears the scramble. This will have to do until Apple provides a permanent solution.

My conclusion is this is a problem which Apple will have to provide a solution for.

Apple has provided a solution. I linked to it in my last comment, which you seem to have ignored.

Linc,

I don't think he's ignoring you, it's just that your post mentions the Automatics Graphics Switching at the end of your post and it's such a small blurb it's easy enough to miss. Heck I did until about 2 minutes ago when I was in middle of writing a response about how you missed his point... then realized you actually did discuss the autographics switching at the end. 🙂

If it's too late for your unit to be repaired under the program, and you don't want to pay for a new logic board, you may be able to stop the panics by disabling automatic graphics switching.

It's also not entirely clear if it would work... only that it's your 'suggestion'. While others have posted a 'clear'

Head over to your System Preferences > Energy Saver, and unselect "Automatic graphics Switching". When toggled (unselected) that it will solve the problem.

I'm on a MBP17", I don't suppose you know if there's any chance Apple Genius Bar can help me?

if this http://i40.tinypic.com/27zdb2x.jpg is what you are talking about Apple won't help you, my logic board was replaced twice and i'm still getting this graphical issues.

I've opened a discussion https://discussions.apple.com/thread/5483475 when i reffer to all this issues after Mavericks instalation.