new i7950, GB-X58A-UD3R build, dropouts persist

[Sloid]

Hi,

If anyone has the patience to read about more dropout problems, I've run out of adjustments to make and would appreciate some suggestions.

Windows 7 64 bit
i7 950
Gigabyte x58 ud3 motherboard
Radeon HD 4350 graphics (running Windows drivers)
6 gig memory
Cubase 5.5.2
MR Tools 1.6
Firmware 1.10

running 1 MR816CSX
System is strictly dedicated to audio, no internet, no WiFi, no games

onboard TI firewire shares an IRQ with three instances (for lack of better word) of ICH10 Family USB Host Controller

DPC Latency Checker shows no problems - Current Latency aprox. 62 us, Absolute Maximum 160 us. "This machine should be able to handle real time streaming...without dropouts."

disabled network adapters in Device Manager
disabled EIST (Speedstep) in BIOS
disabled C1E in BIOS
disabled Thermal Monitor in BIOS
Switched on board firewire to "legacy"
uninstalled Gigabyte Easy Tune
checked "Disable CPU Energy Saving"
switched back from legacy drivers
enabled YSFWUtility to medium setting
plugged FW cable into PSI FW card with VIA chipset
disabled Asalia codec in BIOS
disabled multi-threading
installed APC uninterrupted power supply software utility to attempt to keep voltage stable?
installed graphics drivers from disc (to replace Windows drivers)
adjusted for best performance
switched FW port on MR816
plugged MR firware cable back in to onboard firewire port

running MR buffers at 256 samples...surely that's high enough? I need it to track guitar through amp simm plugins. For now I have installed no plug ins, just Cubase templates with Cubase supplied VSTs & plugs.

...still experiencing dropouts.

I'd really appreciate someone telling me what I'm missing.
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Windows 7 64bit / Cubase 5.5.2 / Intel I7 950 / GB-X58A-UD3R / 3X2 gig Corsair XMS3 DDR3 ram / Radeon HD 4350 PCIe / 3 X SATA HDD / MR816 CSX / Novation Nocturn / Focusrite Liquid Mix 32 / Liquid Mix dedicated pci firewire card / Seasonic S12 650W

[Sloid]

As a test, I hooked up my Tascam US-122L. That was worse, spikes and more dropouts.

Also changed display from 32 bit to 16 bit. Same.

Removed VIA PCI Firewire card. Same.

Updated MB drivers, same.

Going to update the BIOS.
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Windows 7 64bit / Cubase 5.5.2 / Intel I7 950 / GB-X58A-UD3R / 3X2 gig Corsair XMS3 DDR3 ram / Radeon HD 4350 PCIe / 3 X SATA HDD / MR816 CSX / Novation Nocturn / Focusrite Liquid Mix 32 / Liquid Mix dedicated pci firewire card / Seasonic S12 650W