[Voice morph breaking up routinely]

I have a problem with voice morph breaking up routinely.  Suggestions?  I have tried 3 different microphones, have the latest Win 7 drivers and no problem whatsoever with sound in any other program. 

[Latest SL Viewer ATI Radeon Card Issue?]

Thx for all the replies.  It is only sl.  I log in and the fan starts going full blast and doesn't let up.  I minimize sl and wait a minute it stops, I maximize sl...it starts again.  I can only stay logged for short periods due to system heat.  It started the moment I updated and nothing has changed in the system.  

Second Life 3.4.5 (270263) Feb 12 2013 04:43:00 (Second Life Release)
Release Notes

You are at 183,856.0, 265,803.0, 2,501.9 in Vacation Island located at sim6517.agni.lindenlab.com (216.82.11.88:13001)
Second Life Server 13.02.04.269945
Release Notes

CPU: AMD Phenom II X6 1035T Processor (2611.64 MHz)
Memory: 7936 MB
OS Version: Microsoft Windows 7 64-bit Service Pack 1 (Build 7601)
Graphics Card Vendor: ATI Technologies Inc.
Graphics Card: ATI Radeon HD 5700 Series

Windows Graphics Driver Version: 8.17.0010.1129
OpenGL Version: 4.2.11672 Compatibility Profile Context

libcurl Version: libcurl/7.21.1 OpenSSL/0.9.8q zlib/1.2.5 c-ares/1.7.1
J2C Decoder Version: KDU v7.0
Audio Driver Version: FMOD version 3.750000
Qt Webkit Version: 4.7.1 (version number hard-coded)
Voice Server Version: Vivox 3.2.0002.10426

Built with MSVC version 1600
Packets Lost: 30/99,948 (0.0%)

[Radeon 4850 crashes PLEASE HELP!]

My ATI Radeon card is also overheating since the upgrade.  Something is wrong.

[Latest SL Viewer ATI Radeon Card Issue?]

I just switched to the latest sl viewer and it is causing my video card to overheat.  I have tested this every way to Sunday and   it is definietly the sl browser.  I used to be able to use high graphics, now I am overheating at medium.  I am using a ATI Radeon 5700 card on Windows 8 and latest video drivers.