DPC latency spikes = Help urgently needed *please*

Hello

I've come here because I'm desperately in need of some technical help and I'm hoping that maybe somebody here can assist me before it's too late!

I'm a music producer and one half of a dance music act called Far Too Loud (www.myspace.com/fartooloud). Having been DJing club gigs for some time, we're about to take our Live show on the road. For this purpose I have purchased a laptop with the following specs:

Dell Precision M6300
Intel Core2Duo X7900
4GB RAM
NVidia Quattro 1600M gfx
Windows XP Pro

Now this machine had been recommended to me by a few people, and I thought the fact that it was nice and powerful and a "workstation" machine would mean that it would be nice and stable for live use...however I was wrong.

It seems that I'm unable to run my audio at low latency without it suffering from dropouts, clicks and pops. After doing some research into the matter I was advised to try a tool called DPClat to check my machine's DPC latency. Sure enough, the tool revealed that whilst DPC latency was generally fairly low, there are frequent spikes of 8000 microseconds or more which coincide with the audio dropouts:



In an attempt to solve the problem, I have tried:

• Disabling every device driver in the device manager (except for system devices and the system HDD and controller)
• Updating the BIOS from A03 to A10
• Updating the HDD and GFX drivers to the latest versions
• Turning the level of GFX accelleration down to none
• Disabling system restore
• Changing performance option to favour background services instead of programs
• Disabling "Powermizer" feature of NVidia graphics
• Disabling external PCI checking, COM & Printer port, Wifi, LAN, CPU Speedstepping, CPU dynamic accelleration, USB ports and execution prevention from the BIOS
• Fixing the laptop's fan speed using I8KGUI

None of these made the slightest bit of difference to the DPC latency spikes. I have contacted Dell but all they could tell me was that they couldn't help but to install XPerf to try to trace the problem, however this doesn't seem to work with Windows XP.

I am running out of ideas and am seemingly no closer to solving this problem. The laptop is central to our live rig and our first gig is a festival appearance and only weeks away!! Whilst I am fairly technically-minded I am no computer expert, so if any of you can suggest anything which might help then please let me know...I'm losing a lot of hair over this!!!

much appreciated
Dom FTl

 

bump!