MUST HAVE if you are building/adding to your HTPC

[mysticpete]

Hi All
With all the problems of stuttering video and audio streams I see logged on the forums I thought I would pass on one of my secret tools that help me imeasureably when I'm building an HTPC. I have built quite a few systems for people now and there is one tool I just cannt do without. The tool is called "dpclat" and you can download it from Here http://www.thesycon.de/eng/latency_check.shtml.

This tool is totally invaluable when building these systems because Basically what it does is monitor the machines device drivers to see if there are any crappy ones that you are or have installed that could increase latencacies in DPCs which cause drop outs in video and audio.

I have this running on my system all the time and make sure it's the first program I install post first boot up, there is also compatibility with Windows 8 in the latest version and it also works on WHS2011.

I've taken a extract from the web site below and there is a good .pdf doc at the bottom of the link page http://www.thesycon.de/eng/latency_check.shtml.

believe me that if you have stuttering video and/or audio problems then this little tool could save you a lot of headaches, the only thing that it does not do is identify the problem driver, so it's a case of inspector Clueso in the Device Manager

"If any kernel-mode device driver in your Windows system is implemented improperly and causes excessive latencies of Deferred Procedure Calls (DPCs) then drop-outs will probably occur when you use real-time audio or video streaming applications. For an explanation of this effect see Background information below.

The DPC Latency Checker tool determines the maximum DPC latency that occurs on your Windows system and thus enables you to check the real-time capabilities of your computer. DPC Latency Checker works independently of any external hardware. Using this tool may be helpful in the following situations:

- You experience interruptions (drop-outs) in a flow of data processed in real-time, for example an audio stream, video stream or a sequence of measuring data, and you want to find out the reason for this problem.

- You want to verify that your Windows system is configured properly so that it is capable of handling real-time data transfer before you install the corresponding streaming application.

- You want to check if a particular computer system is suitable for streaming applications, for example before you buy this system.

In many cases DPC latency problems are caused by specific types of devices. So you should try the device types listed below first.

- Network adapters for Ethernet and Wireless LAN (W-LAN)
- Internal modems
- Internal sound devices (on-board sound systems)
- Any PCI or PCI Express add-on card, any PCCard or ExpressCard, e.g. TV tuner cards, ISDN or DSL adapters, modems, etc.


Have fun and I hope there are no surprises when you run this

Mysticpete

[Multi Media PC]

Perfect tool thx for sharing!

[Saentist]

now i need new driver for my USB Terratec cinergy S2 USB HD
coz is verry laggy
[hr]
i thing better one tool is LatencyMon
at less show problematic drivers

[rolando]

Thanks for this info. I found out that my nVidia GT240 had a terrible DPC latency. I went and replaced it with a cheap nVidia GT610, which turned out to be 3 times better on DPC latency. I also found out that Windows 8 has terrible DPC latency because of the way they rewrote the kernel to save power. Also, getting XBMC to autostart is a challenge in Windows 8. Simple story is, don't have a HTPC that runs Windows 8, stick with Windows 7 or Linux.

[mysticpete]

Thanks for this info. I found out that my nVidia GT240 had a terrible DPC latency. I went and replaced it with a cheap nVidia GT610, which turned out to be 3 times better on DPC latency. I also found out that Windows 8 has terrible DPC latency because of the way they rewrote the kernel to save power. Also, getting XBMC to autostart is a challenge in Windows 8. Simple story is, don't have a HTPC that runs Windows 8, stick with Windows 7 or Linux.

Yes I've noticed the amount of time it takes to fire up XBMC in 2008 Server also, but mine usually stays on 24/7

I'm glad this program was of assistance, still runs 24/7 just in case windows does a backdoor driver update

[PRKid]

Thanks for the both leads on these programs. They actually helped me ensuring proper power option and cpu throttling.

One issue that I did run into is that the DPC Latency Checker (dpclat v1.3.0) informs me that my "The machine should be able to handle real-time streaming of audio and/or video data without drop-outs.", whereas, the LatencyMon highlights several issues, such as, one or more DPC routines of a driver which is running far too long, potential WLAN network issue, for better power management disable CPU throttling in Control Panel, and, update BIOS.

I did disable the CPU throttling yet, the issue is still highlighted -- not sure why!!

This is my first running these, thus, any inputs from the team would be great. Thank you!

Attached is a pic of screen.



PRKid

[mysticpete]

Thanks for the feedback PRKid, I think the DPC latency checker is more tuned to effects on Video performace, I have not come across LatencyMon before http://www.resplendence.com/latencymon so will look more into this tool as it appears to be more comprehensive....

Thanks
Mysticpete

[PRKid]

Thanks for the feedback PRKid, I think the DPC latency checker is more tuned to effects on Video performace, I have not come across LatencyMon before http://www.resplendence.com/latencymon so will look more into this tool as it appears to be more comprehensive....

Thanks
Mysticpete

Thanks Mysticpete! As I mentioned, with dpclat it seems all is "good". My readings are all "green". By the way, as I use dpclat, what can I infer from the results? Based on your experience, how can I use the results to improve the performance? Thanks!

PRKid

[mysticpete]

@PRKId

It's all about drivers really, because I run dpclat 24/7 when I add anything to the system I look to see the effect that those drives have on the overall latency, it's really the only way I have found to ensure that the drivers installed do not interfere with video performance. its a matter of trial and error if when you first run dpclat that you have consistant red bars, then it's a matter of following a routine of disabling software drivers from device manager to try and track down the culprit.

That's why I'm interested to see if 'LatencyMon' it any more specific in determining a possible cause of the latency.

Mysticpete

[PRKid]

Thanks Mysticpete! This is certainly new to me, thus, will keep playing and learning, and, will post my findings.

[Rave]

I see CPU throttling has been mentioned above and I concur with this advice. I had stuttering in Windows Media Center that was caused by this. The two common names for this in BIOS are:

• AMD: Cool N Quiet (for desktop PCs)
• Intel: SpeedStep

My full post on TBS forums:
Flickering/distortion/break up in Windows Media Center

Wiki: Cool N Quiet

Hope this helps.