P35 Motherboards and DPC Latency Spiking

[chriskwarren]

I have some time for upgrading now, and I want to use my Q6600 and DDR2 and the X58 won't support that. I am thinking about a P45 board, as I have never used Crossfire (but would actually like to try it...if I did, would like 16x / 16x lanes). I am thinking of the Rampage (X48...on sale now), or the Gigabyte X48 DQ6 or the P45 DQ6 board (like the TPM chip and new Raid features).

Not sure I am patient enough to wait for new revision P45 boards / new bioses to work the bugs out. If i don't go with a Gigabyte P45 board then I might go with the Rampage and then RMA my DS3P with the latency issues

[Lsdmeasap]

Yeah, I really like the hardware raid and onboard ram for that on the P45-DQ6, that is what I plan to save and get. Hopefully a rev or two will be done by the time I am ready to buy one

[fimpen_b]

Beta BIOS v. F4h for GA-EP35-DS4 rev. 2.1 EP35DS4.F4H
Same results as F4b regarding the DPC latency. I don't really know what this version fixes. Maybe the problem of not being able to change CPU voltage, haven't checked.

[aspenleaf]

Thanks for posting the 4H BIOS for the EP35-DS4. I hadn't been notified by Gigabyte.

I ran some quick tests, and it does indeed allow you to change the CPU voltage, and it will hold the settings. The max DPC latency was 15us, and most of the time it was between 4us and 6us. I'll post again after running it for a while to try to uncover any problems.

I'm glad to see Gigabyte is still working on this.

[kpo6969]

Any thoughts from the community on this:
origional post:
AnandTech - Gigabyte Boards and DPC Latency

"Hi, i think i have good news, i had the same DPC latency problem with my Gigabyte GA-P35-DS3 Board (glitchy sound and performance issues) and i searched for a solution for about 2 Weeks now. I think i have it. There is a faulty Driver in Vista which generates a LOT of DPCs, when sound and/or Video is played. The driver is the one for the MMCSS service, which has the function to reduce gliching ( yeah, i know, that service does a BAD job :D ) To deactive it, you have to follow this procedure (BIG thanks to Courtney on http://blogs.technet.com/markr...7/1833290.aspx#1841934 !!!! ):


"my first thought was to disable the MMCS service, but the Windows Audio service is dependent on it.

So I ran regedit, and changed the key

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Servic es\Audiosrv\DependOnService

Just remove MMCS from that key in the list, and set MMCS to disabled in services, then reboot.

As soon as I rebooted I was able to copy files at 40mb/s+ while listening to audio

-Courtney


I still have light DPC lag, but it's harmless because the numbers of requests don't increase anymore, when i'm using sound and graphics.

I hope this helps, good luck !"

Mark's Blog : Vista Multimedia Playback and Network Throughput

"Solution found
my first thought was to disable the MMCS service, but the Windows Audio service is dependent on it.
So I ran regedit, and changed the key
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Servic es\Audiosrv\DependOnService
Just remove MMCS from that key in the list, and set MMCS to disabled in services, then reboot.
As soon as I rebooted I was able to copy files at 40mb/s+ while listening to audio
-Courtney"

[Dark AvaloN]

Did that. Same thing, I have no problems in audio playback but get some red spikes and a very sluggish vista at times.



This is what I get in iddle. It gets worse if I start something more heavy.

[kpo6969]

That's a lot better than I get @ idle doing nothing.

[kpo6969]

I guess Anand decided to lock their thread on this issue, interesting :

AnandTech - Gigabyte Boards and DPC Latency
DPC latency issue isn't exclusive to Gigabyte boards and isn't something to be nervous about unless it occurs consistently and you're actually experiencing issues related to it. It's not like your usual stability test that has to pass certain amount of time without a fail.

The issue specific to the Gigabyte boards has been discussed, so this thread is closed. If any of you want/need to discuss this matter further, feel free to start a new thread. Be specific to issues and respective to fellow forummers. Please note any new thread regarding this issue will be closely monitored, and any violation of forum rule will not be tolerated. If you've received a personal warning(s) from a mod, pay close attention to the forum rules since warnings are cumulative.

AnandTech Moderator lopri

[chriskwarren]

Yeah I noticed too...if Gigabyte issues beta bioses to fix an issue, is it not resolved or concluded until a final bios is released?

[kpo6969]

To Gigabyte,
You may have forgotten us but we have not forgotten the sub-standard support:

Neowin.net - Gigabyte pushes into mid-range motherboard market