High DPC Latency Spikes

[Zino]

I welcome gurus and diligent googlers to find a solution to my long lasting problem with DPC latency.

I've had the problem with ups and downs in DPC latency for months now, and I think it's affecting my PC's performance in games as well, the crackling sounds always give me 20-30 FPS drops.

It happens when I browse and load a website, and it spikes worse if I have Spotify playing music on top of that.

Here's how it can look (I'm running the dpc latency checker while loading some websites):

And here's LatencyMon's report on the execution times of various drivers:

And here are my computer specifications:

OS Version: Microsoft Windows 8 Professional, 64 bit

Processor: Intel® Core i5-3570K CPU @ 3.40GHz, Intel64 Family 6 Model 58 Stepping 9

Processor Count: 4

RAM: 16271 Mb

Graphics Card: NVIDIA GeForce GTX 680, -2048 Mb

Hard Drives: C: Total - 953867 MB, Free - 849518 MB; D: Total - 244190 MB, Free - 86103 MB;

Motherboard: ASRock, Z77 Pro4-M

Antivirus: Avast! Internet Security

Now, I'm up for testing anything, so if you have any crazy ideas, just shoot.

Thanks in advance!

I'm contemplating whether to buy a new motherboard and PSU or not. It seems like my only options left.

[Porkey]

(woo, first post)

I, too, have suffered from this dreadful PC defect for a year now. Unfortunately, I've found that it's likely just my motherboard (specifically the chipset I'm on).

But, I have done more than plenty of Googling to find a solution. Although I've not found a solution that works for me due to my garbage motherboard,

I've heard of many people solving their troubles by trying the following:

 

Solution 1: Check if your PSU is powerful enough to run all of your hardware. It's not a very helpful

suggestion, but if your PSU's 12v rail doesn't have enough amperage to run all of your

hardware, this can lead to a large number of issues. High DPC latency included.

 

You mentioned that you're running a 680; whenever I need a rough estimate of how much amperage

I need on my 12v, I normally go to MSI's list of graphics cards and power requirements:

http://forum-en.msi.com/faq/article/power-requirements-for-graphics-cards

 

The 680 is listed as consuming 38A of power on the 12v rails.

This in mind, I'd say you need a PSU with somewhere along the lines of

60A, just to be completely safe. Everyone knows, you have to

over-compensate just a little bit when it comes to power supplies.

 

Solution 2: Disabling HPET (High Precision Event Timer) in the BIOS

HPET was supposed to be a super-accurate hardware timer for programs to use

to synchronize with real time. At first I thought it would be a bad idea to disable a

high-precision system timer, but I've never heard of disabling it having negative

side effects for people who can disable it. Apparently Windows 8 doesn't even

make use of it. People who have had DPC latency issues often see big improvements

after disabling HPET, but I've also read that if it doesn't do anything after disabling it,

then it's probably better to leave it on, which makes sense to me.

 

Solution 3: Disable power saving features of your CPU in the BIOS. Things like SpeedStep, or even TurboBoost.

From what I've read this is one of the big reasons why people have advised

disabling Intel power saving features in the past. I haven't heard of newer Intel CPUs doing this

(or perhaps not until now?), but many older Intel CPUs tend to cause large DPC latency

spikes when switching between power states/frequencies. Some people have found that

disabling these features helps, some haven't.

 

Solution 4: Disable power saving functions of your GPU.

I've read that NVidia GPUs, integrated and dedicated, have caused DPC latency issues

in the past, in the same way that Intel processors have been known to cause issues.

Some people have found that they get large DPC latency spikes when their card/chip

goes from "fast/3D" clocks to "power savng/idle" clocks. I haven't done as much reading

on this as I have the other solutions, but apparently, far into the past, this was due to

PowerMizer, which managed your GPU's power states. Disabling PowerMizer would

keep your GPU at full clock speeds all the time, but it solved some peoples' DPC problems.

 

Solution 5: Disabling Hardware in Device Manager
Multiple times, I remember reading about people disabling this or that device

in Device Manager, and finding their DPC issues resolved. The most popular thing

I can remember people disabling to cure this disease is their network adapters.

Other times, I've heard that USB devices, or even USB controllers themselves

have caused DPC latency issues.

 

Solution 6: TimerResolution

As an absolute last resort, there is a little application called TimerResolution for Windows.

It's a little quite a bit complicated to explain how this program works, but what it does, is it's a tiny

program that you can set to run as frequently as your HPET timer will allow it.

Every half-millisecond, 1.5 milliseconds, or whatever your HPET limits you to, this program

will run a small execution on your CPU that keeps your CPU "awake." The execution

consumes literally no resources, and running this program seems to be the solution

that works most frequently, or so I've read.

 

All you have to do is download the appropriate version of TimerResolution for your

operating system, open it, click "Maximum" and minimize the program. Do not close

it; it has to run in the background (every X milliseconds) to keep your CPU from

"sleeping" when it's not needed. TimerResolution probably won't reduce your

DPC latency to "normal" numbers, but it a lot of people seem to report it

reducing DPC latency, sometimes by extremely large numbers.

 

 

 

 

 

Also, some links from my "notes" that may help you, or anyone who finds this thread through Google.

I would highly suggest following these links, as they will certainly contain

possible solutions that I haven't mentioned here. Some of these solutions

are regarded as taboo because they're rumored to do bad things, but

you should read about them anyway:

http://www.lucashale.com/timer-resolution/

http://www.gearbytes.com/2012/08/dpc-tweaking-guide-for-av-gaming/

https://forums.geforce.com/default/topic/743202/geforce-drivers/dpc-latency-stuttering-high-gpu-usage-the-search-for-usable-older-drivers-or-a-fix-/

http://forums.guru3d.com/showthread.php?t=384398

http://forums.guru3d.com/showthread.php?t=374210 - Read this, (I think this thread has a bunch of interesting fixes)

http://forums.guru3d.com/showthread.php?t=374210&page=17 - then read this. "disabledynamictick" tweak is apparently ill advised.

http://www.msfn.org/board/topic/140263-how-to-get-the-cause-of-high-cpu-usage-by-dpc-interrupt/

http://hardforum.com/showthread.php?t=1600122

https://forums.geforce.com/default/topic/606941/nvidia-driver-dpc-latency-input-lag/ - This, and the below link, are related to DPC issues with NV 600 series.

http://www.overclock.net/t/1388836/input-lag-in-nvidia-drivers

http://www.sevenforums.com/network-sharing/52935-network-usage-causes-high-dpc-latency.html

 

For those of you who don't know what living with high DPC latency is like, please watch these videos.

 

 

Edit - WOW this post ended up a lot longer than I thought it would be!