Web Browsers Freezing Mountain Lion

I upgraded to Mountain Lion over the weekend and I am really beginning to regret it. I went the upgrade route and soon after the upgrade was performed I began to experience system freezes while using Chrome. After a couple freezes I thought it might be best to use Safari. The problem occurred while using Safari as well. To the best of my memory these crashes generally occurred on pages that contained video. I can't say for sure because I may not have reached the bottom of the page before the freeze occurred. I performed a clean install after many freezes but the problem continues.

The freeze begins with a fraction of second where small squares appear on the screen. The screen then freezes but audio continues. During this time I am able to move the mouse but am unable to click on anything. Only option at that point is to use the power button. A crash log is not generated in the diagnostic reports. I'm not sure what is helpful to paste from the system logs but will provide anything you ask for. I'm a reasonably technically literate user but completely new to the support forums as my previous Macs did not have any serious problems.

I am a graphic designer and this is my primary machine and browser crashes are seriously inhibiting my ability to build websites. I would greatly appreciate any advice you can offer.

Below is my system as it is now. Crashes occurred even with a bare bones fresh install.

Hardware Information:

Mac Pro - model: MacPro5,1

1 2.8 GHz Quad-Core Intel Xeon CPU: 4 cores

12 GB RAM

Startup Items:

tap - Path: /Library/StartupItems/tap

tun - Path: /Library/StartupItems/tun

System Software:

OS X 10.8.2 (12C60) - Uptime: 0 days 0:18

Disk Information:

HL-DT-ST DVD-RW GH61N

WDC WD1001FALS-41Y6A0 disk0 : (1 TB)

disk0s1 (disk0s1) <not mounted>: 209.7 MB

WDC1TB (disk0s2) /: 999.35 GB (416.43 GB free)

Recovery HD (disk0s3) <not mounted>: 650 MB

WDC WD2002FAEX-007BA0 disk2 : (2 TB)

disk2s1 (disk2s1) <not mounted>: 209.7 MB

WDC2TB-1 (disk2s2) /Volumes/WDC2TB-1: 2 TB (811.36 GB free)

WDC WD6401AALS-00L3B2 disk3 : (640.14 GB)

disk3s1 (disk3s1) <not mounted>: 32 KB

WDC640-2 (disk3s3) /Volumes/WDC640-2: 640 GB (332.67 GB free)

WDC WD6401AALS-00L3B2 disk1 : (640.14 GB)

disk1s1 (disk1s1) <not mounted>: 209.7 MB

WDC640-1 (disk1s2) /Volumes/WDC640-1: 639.79 GB (202 GB free)

USB Information:

Logitech USB-PS/2 Optical Mouse

Apple, Inc Apple Keyboard

Apple Inc. BRCM2046 Hub

Apple Inc. Bluetooth USB Host Controller

Creative Technology Creative USB Headset

FireWire Information:

Kernel Extensions:

foo.tun Version: 1.0

foo.tap Version: 1.0

Problem System Launch Daemons:

Problem System Launch Agents:

[failed] com.apple.afpstat.plist

Launch Daemons:

[loaded] com.adobe.fpsaud.plist

[loaded] com.adobe.SwitchBoard.plist

[loaded] com.microsoft.office.licensing.helper.plist

Launch Agents:

[not loaded] com.adobe.AAM.Updater-1.0.plist

[loaded] com.extensis.FMCore.plist

User Launch Agents:

[loaded] com.google.keystone.agent.plist

User Login Items:

iTunesHelper

3rd Party Preference Panes:

Flash Player

Internet Plug-ins:

AdobePDFViewer.plugin

Flash Player.plugin

FlashPlayer-10.6.plugin

JavaAppletPlugin.plugin

QuickTime Plugin.plugin

SharePointBrowserPlugin.plugin

Silverlight.plugin

User Internet Plug-ins:

Bad Fonts:

None

Top Processes:

3.2 % WindowServer

0.9 % EtreCheck

0.6 % mds

0.5 % fontd

0.2 % mdworker

0.0 % loginwindow

0.0 % Finder

0.0 % Dock

0.0 % imagent

Video Card:

ATI Radeon HD 5870

(I included this as I have seen other posts connecting this to specific video cards)