Solution Found - It is NOT an Intel driver(s) issue.
It's cured by changing the default installation path when installing ATI Catalyst drivers from...
C:\Program Files\ATI Technologies to C:\Program Files\ATI
Bad path coding here that prevents CIM files from being installed in their hard coded destination. It's an issue in 9.1 (needed for FutureMark benchmarking)/9.2/9.3/9.4 versions of Catalyst.
Without the CIM files it will clash with the Intel drivers royally. With the proper CIM files, there's no Event Viewer errors, and Matrix+Chipset drivers aren't complaining (no weird lines; no lockups; no BSODs).
Hopefully this will cure this headache between these two different company drivers for others, too!
Motherboard: P5Q Pro with Version 2002 BIOS
Processor: Intel C2D "Wolfdale" E8500 3.1Ghz
Memory: 2x2GB Corsair Dominator @ 1066Mhz
Videocard: Sapphire HD4870 DDR5 512MB
HDD: 2x150GB WD RaptorX - RAID 0/4 partitions