Well I finally built the new system, i7 3770k CPU, Asus P8Z77V-LK motherboard with 16gb ram (running Win 7 x64 and Sonar X2) and so far i'm extremely happy. Compared to the old core2duo i've been flogging for years this thing is a beast! 

So i've been tweaking the system to reduce dpc latency and using the dpc latency checker i've got the system down to between 17-35usecs with the occasional spike of around 270usecs. I'm pretty happy with that as a DIY'er however i'm wondering what the occasional 270usec spike might be, not that its causing dropouts (at this stage) but just wondering if I can eliminate it altogether. I ran latencymon and it seems that the USB 1.1 and 2.0 drivers are the highest culprit but they seem to be the latest version (in fact latencymon occasionally reports that the system may not be suitable for real time audio streaming - again the usb drivers seem to be the culprits.) 

So I guess i'm putting it out there for any further tips or advice on how to tweak this a little further. Cheers in advance.  

Some more info that may help, i'm currently using the mobo onboard graphics but i do have an ATI HD5450 card I could install if that helps??? 

I've disabled any auto cpu performance throttling options and the HPET in the bios. All on board sound etc disabled, all power schemes set to max or always on etc etc, no firewall or virus programs on, and i've trimmed down start up and background services a little (some items that I felt comfortable doing!)

Also there is no overclocking on the cpu (yet.) I'll see how I go with that down the track and may get someone to help with that - I did fit a larger non stock cpu fan for that purpose (one day.)

Look forward to any comments, cheers. 

USB 1.1? That hasn't been around for years and you don't have that on a new motherboard. USB 2.0 and probably the new USB 3.0. I just built a new system with a Gigabyte Z77X UD5H motherboard. I accidentally installed a Gigabyte system configuration and monitoring utility and that was causing me high latency spikes. Once I removed that, my latency settled down.

 I didnt install any monitoring utilities for the reason you mention, seems like lots of people experience what you did. On the latencymon report it definitely states USB 1.1 and USB 2.0 drivers, that is a bit odd now that you mention it. Maybe I don't have the latest drivers installed ???

Any wireless networking device turned on ?

No wireless on. The driver causing issues is usbport.sys. When you google latency with usbport.sys there are lots of articles! None which have a solution that I can find, unfortunately.

Have a look here if it's related :


http://forums.mydigitallife.info/threads/24666-The-Windows-7-SP1-USB-Driver-Bug-(what-it-is-and-how-to-fix-it)

One of the link points to :
http://support.microsoft.com/kb/2529073

I have my Win 7 update turned on and found that from my Windows installed updates **, I've already received the KB2529073.

** Control Panel, type in "update" to the search control panel
- Windows Update - View update history - Sort list by name
scroll down the list to "Update for Windows 7 for x64-based Systems (KB...) and see if it's there.

Thanks Albert, interesting reading. Well I haven't installed SP1 so I wouldn't have the problem listed, however thanks to your article I did discover that the usbport.sys driver I have is not the latest. I will update and see if that makes a difference.

Appreciate your input.

You are welcome!

When I setup my new system early last year, there was always some initial issues. After going through some patching up with drivers, etc..(not that I'm aware of every step of the updates, as some updates may have just got it right..) I finally have a good workable system.

Hope the issue is resolved soonest.