DPC latency rises when running RMClock/Notebook Hardware Control

Hello all,

I've been attempting to get my laptop to increase its clock speed more robustly by running RightMark CPU Clock utility. Unfortunately, every time I activate any of the power profiles, the system becomes extremely unresponsive.

Within minutes of activating a profile, Process Explorer shows DPC CPU usage increasing up to 10-30%. DPC Latency Checker shows the bars steadily increase into the red almost as soon as the profile is activated.

I've tried running other utilities to help me to the same end, SpeedSwitchXP and Notebook Hardware Control. NHC creates the exact same issue, while SpeedSwitchXP does not seem to do anything at all. It just shows the CPU at max speed while doing nothing to actually increase the clock

I'm at my wit's end trying to solve this issue, so any help would be greatly appreciated. I've tried googling this problem to no avail.

Thanks for any help,

Stan


The system:
Inspiron 6400 running Windows XP SP3
Intel Core Duo T2500, 1GB RAM


I should probably mention that I'm running a relatively virgin XP install that's maybe 3-4 months old. Other than the wlan/video drivers, there isn't any crud running in the background that would clash with RTClock, and no antivirus either.

 

if i understand you right...your trying to overclock? If so you can donate money to setFSB and get their program. It is the main program i know that is used to OC. Also check my link in my sig it has info on setFSB and otherways to help you out. If i get off my lazy butt in the next couple of days i got a ton of links and ways to help out various uses...just haven't been motivated enough to add everything

 

No, I am not attempting to overclock. I merely want my computer to actually adjust its CPU speed up to its factory-set maximum of 2GHz during periods of increased demand. This is what is supposed to normally happen with Intel SpeedStep processors. I've read that support for this feature has been flaky in Windows XP. It was supposed to have been fixed with SP3. No such luck for me - the speed as reported by progs such as RTClock or HWInfo does adjust up and down, yet it does so in a sporadic way, seemingly independent of how busy the CPU really is.

Perhaps this feature does work as intended for applications which keep the CPU under 100% load most of the time, like 3D games. However I need max performance for shorter periods of time - adjusting the sliders in Adobe Lightroom, for example - and the 3-5 secs while the CPU is under full load are spent at 1GHz. To that end, RTClock does a great job of adjusting the speed up and down with demand, and Lightroom responsiveness increases significantly. Yet along come DPC latency spikes and system responsiveness deteriorates progressively to the point of being unusable.

Based on what I've read, selecting the Home/Office Desk or Always On power schemes is meant to actually keep the CPU at its max speed rather than increase/decrease it based on performance. And although Windows reports the CPU as running at 2GHz, other utilities which show clock speed at a glance, as well as the actual performance of the system, indicate otherwise.

 

After a bit more research, I have found a utility called RATTV3 which logs the DPC latency of individual drivers. I thought this would find the smoking gun, the one driver responsible for the latency spikes with RTClock running. Unfortunately, I've had no such luck. The latency of DPCs of all the drivers increases more or less in tandem. The worst offenders are sthda.sys, VIDEOPRT.SYS, ntkrnlpa.exe, and NDIS.sys. The latency for them goes well up above 1ms for a fair sized portion of their DPCs. They are all legitimate drivers, however, and knowing this doesn't bring me any closer to solving the problem.

At this point, I think I will have to give up on getting Windows XP to up its clock speed like I want. I don't want to retire my laptop just yet since it's still running great, so I might have to get more ram and give Windows 7 a shot. I'll just have to hope that proper EIST management (if it truly works) will offset the performance hit of running the Windows 7 instead of XP.