Originally Posted by cookieboyeli
So much misinformation in this thread Over 100uS current Interrupt to DPC latency is BAD.
In fact, over 50uS is not good either. Though it is certainly not unacceptable.
This is how a system should be at idle:LatencyMon Idle Usage!
Remember, a 1000Hz mouse relies on your system being able to process the input every 1ms, aka every 1000uS.
If you have regular levels above about 100uS or that bounce all over the place and get spikes you're going to be introducing jitter and stutters not only on your mouse movement's update rate but jitter and stutter on your on your audio and video rendering and presentation chain.
Then end result is a massive degradation in system FLUIDITY (kind of like what using vsync does but with your mouse and audio).
It will make tracking targets harder and screw up your aim. You may realistically not NOTICE it happening, but it IS still happening, and once you fix it you will then notice how it ISN'T happening.
The same issues is described here where other factors negatively influence a mouse's polling rate, except the cause here is primarily from something else:
I've made a few half-assed guides on lowering overall Interrupt (DPC/ISR) latency. Including those 500uS+ spikes from Nvidia drivers.
Some of it is in this thread. It's incomplete as hell though: http://forums.guru3d.com/showthread.php?s=05b8aa692c06608317d3a63235d17495&t=406260
You may not be able to get rid of them entirely, but you can certainly reduce their frequency significantly!
I may only get a spike every few minutes now.My average idle DPC latency is 2uS
Work towards this idle usage:
(In this old picture I had frequency set to drop at idle as I was still testing).
I also don't need to disable TONS of power saving features and idle at 200watts to do this, I idle at 66w and have most power saving features enabled actually. Two that you should change for sure though are disable C7 states, and set processor minimum frequency to 100% in power options. If your system is configured correctly you will have 0.1 to 0.7w idle power increase from doing that.
I recommend keeping Nvidia power usage at optimized instead of max performance, in all my testing it works flawlessly at lowering idle power usage without causing problems during load like balanced does. It's as if Nvidia knows what they're doing.
Depending on your system and mouse's performance, your polling rate might be all over the place, varying wildly from 400-1600Hz and causing major spikes. You can test your mouse's performance with Mouse Movement Recorder in the MarkC Mouse Fix:
If anyone needs help or advice on optimizing DPC latency let me know, I spend about 30 hours a week on teamviewer helping people for fun. EDIT About DPC latency under load!
I understand that is important too. However, if you've lowered the idle DPC latency to the absolute minimum your system can physically achieve, you have already done 95% of what you can do to lower the load DPC latency to IT'S