Intel WifiLink 4965 AGN Driver's DPC Latencies causing audio glitches in Windows 7 X64 (RTM)

[idata]

After many tests I can ensure that the wireles adapter Intel WifiLink 4965 AGN is causing high DPC Latencies with an interval of 10 micro-seconds in Windows 7 64 bit (Release to Manufacturer). I have tried the latest drivers for Windows Vista 64 bit (12.4.3.9) and Microsoft's drivers included in Windows 7 with the same results: high DPC Latencies with an interval of 10 micro-seconds and eventual very high DPC Latencies causing audio glitches with a length of up to one second. Is there any specific driver for Windows 7 64 bit (Release to Manufacturer) that solves this issue?? Will there be??

[idata]

Make/Model Laptop: Sony Vaio FW46GJ

Product: 5100AGN

OS: Windows 7 Professional x64

Driver Version: 13.2.1.5 (9/10/2010)

Problem: High DPC spikes constantly, causing audio problems.

Tests done: Disabled Wireless driver - DPC spikes almost completely go away and audio is normal, re-enabled and DPC spikes come back and audio glitches again.

[idata]

Make/Model Laptop: Lenovo Thinkpad R61 (2GHz Intel Core Duo)

Product: 4965AGN

OS: Windows 7 Ultimate x64

Driver Version: 13.2.0.30 (3/18/2010)

Problem: ~3000µs DPC spikes every 10 seconds

Tests done: Disable 4965AGN driver - DPC spikes disappear, re-enable and DPC spikes reappear

[idata]

http://en.community.dell.com/dell-blogs/Direct2Dell/b/direct2dell/archive/2010/02/19/update-on-dpc-latency-for-alienware-m17x-customers.aspx http://en.community.dell.com/dell-blogs/Direct2Dell/b/direct2dell/archive/2010/02/19/update-on-dpc-latency-for-alienware-m17x-customers.aspx

http://en.community.dell.com/dell-blogs/Direct2Dell/b/direct2dell/archive/2009/11/18/dell-dpc-latency-and-you.aspx http://en.community.dell.com/dell-blogs/Direct2Dell/b/direct2dell/archive/2009/11/18/dell-dpc-latency-and-you.aspx

[idata]

Each driver release goes wronger so I definetly decided to replace my Intel 4965 AGN by a Broadcom BCM 4321 and I got rid of both my DPC latencies spikes and signal dropouts. After some testing I noticed that Intel 4965 AGN reports more signal than what it actually gets. So after this I can confirm that all Intel 4965 AGN are faulty or have faulty drivers.

[PRich9]

I would change my network card also but HP doesn't allow it.

I have the same latencies and I hate it.

Do you know if newer Intel WiFi cards work better?

[Ilene_K_Intel]

Just wanted to give you all an update on this issue.

Intel engineering is continuing to research and root cause the problem. There is a fix in 13.2.1.5 and later for the 5000 and 6000 series adapters. The information you have provided has been very helpful. Please continue to test with the newest drivers and report your results on this Forum. I will post a notification here when we have a fix for the Intel® PRO/Wireless 3945ABG Network Connection and Intel® Wireless WiFi Link 4965AGN adapters.

Thank you,

Ilenek

Intel Customer Support

[idata]

When can we expect a fix for 4965AGN??

Thanks,

Osho

[idata]

Yes, please let us know when we can expect a fix with the Intel 4965AGN wireless adapter and Windows 7 64bit systems.

I too am using a Lenovo T61p notebook and have been having these micro stutters with the system.

Perhaps Intel should work with Lenovo and come to a proper solution with this issue?

Please let us know.

Thank you.

[idata]

Machine: Lenovo T61 Thinkpad

OS: Windows 7 Pro x86

Device: 4965 AGN

Driver Installed: 13.4.0.139

Date: 07/10/2010

High latency spikes measured with device enabled.

No problem with device disabled.

I am looking forward to seeing an updated driver so I can use my laptop with wireless. Any news?

[idata]

Thanks for the 2010-11-16 update from Ilenek at Intel (below), but since this problem has not been solved in over a year, I am beginning to conclude that it can't be solved (or the engineers have more pressing problems). I use my computer for live music production and my only option is to disable the 4955AGN in Device Manager to avoid audio artifacts due to spikes of DPC latencies of well over 2000 microseconds every 10 seconds or so.

Here are my system specs:

Wireless = Intel WiFi Link 4955AGN

Driver = Intel; Dated 10/7/2010; Version 13.4.0.139

Laptop = Lenovo T61p Intel Core 2 Duo 2.4 GHz

OS = Win 7 64 bit

Memory = 4 GB

It sounds like the problem has been fixed in the newer Intel WiFi products (5000 and 6000 series adapters). I'll check with Lenovo to see if I can upgrade my T61p to one of the newer adapters. Otherwise, it looks like I may have to wait until I upgrade the entire computer before I can use audio with the WiFi on.

-----------------------------------------------------------------------------------------------------------------------------------------

Nov 16, 2010

Re: Intel WifiLink 4965 AGN Driver's DPC Latencies causing audio glitches in Windows 7 X64 (RTM)

Just wanted to give you all an update on this issue.

Intel engineering is continuing to research and root cause the problem. There is a fix in 13.2.1.5 and later for the 5000 and 6000 series adapters. The information you have provided has been very helpful. Please continue to test with the newest drivers and report your results on this Forum. I will post a notification here when we have a fix for the Intel® PRO/Wireless 3945ABG Network Connection and Intel® Wireless WiFi Link 4965AGN adapters.

Thank you,

Ilenek

Intel Customer Support

[idata]

In follow up to my last post (as a guest – post # 79 in this thread), I just ordered one of the newer Intel PCIe cards for my Lenovo T61p laptop (Intel® Centrino® Ultimate-N 6300 (633ANHMW); $35.24 at Amazon). It looks like the 5300 series and below are now listed as "legacy" hardware by Intel and therefore they are probably a low priority for the engineers to update the drivers for new OS's (like Windows 7 64). As Ilenek from Intel Customer Support points out, the drivers with the new adapters have solved the DPC latency issue. At this point, I think that 35 bucks is worth it rather than waiting (perhaps in vain) that the Intel will ever release a driver fix for the - now legacy - 4965AGN. I'll post again after I test the 633ANHMW to see if the new drivers fix the problem on my machine.

[idata]

is it realitively easy / possible at home to replace the WiFi module? or are you taking your laptop to some proffesionals?

[idata]

The location of the card varies by manufacturer. In my case, the card slot is under the keyboard; which means I'll have to take the keyboard off to get to it. If you are interested, check your machines website for a hardware maintenance manual (NOT the User's Manual) that tells you how to access the card slot. For instance, for my Lenovo T61p, the manual is located her:

http://download.lenovo.com/ibmdl/pub/pc/pccbbs/mobiles_pdf/42x3546_03.pdf http://download.lenovo.com/ibmdl/pub/pc/pccbbs/mobiles_pdf/42x3546_03.pdf

It is more involved than, say, changing memory modules, but not super difficult. But before your order a newer WiFi adapter, you may want to wait until I get mine installed to see if the 13.2.1.5 or later drivers fix the DPC latency under Win 7 64.

[idata]

Great, thanks! So please, do report when you get yours! :)

[idata]

UPDATE: Unfortunately, after installing the new, 633ANHMW, card, I received this error at boot: ""Error 1802 Unauthorized network card is plugged in, Power off and remove the mini PCI network card."

This could either be due to the fact that I ordered the short ("half-mini") version of the mini PCIe card, or Lenovo needs to do a BIOS update to accept these new cards in their machines. Intel only makes the 6000 series cards in the newer, half-mini PCIe form factor.

I'm going to order the full-length version of one of Intel's newer mini PCI wireless cards (5300 Ultimate N Wi-Fi Link) and if I still have problems, I'll contact Lenovo to see what the problem is upgrading the wireless cards in their laptops. Our Intel contributor to this thread (Ilene) indicated that the current drivers for the 5000 and 6000 series fixed the DPC latency problems. We'll see.

I'll post again after I install the 5300 card.

[idata]

Unfortunately, you cannot upgrade your card to a 5300 or a 6xxx series adapter because IBM/Lenovo "lock" their BIOSes and will not allow the machine to boot up if it recognizes a foreign card. So in order to stay stock, the 4965AGN is the last supported Wireless-N card that can be used for the T61/p line.

However, you can install a modified BIOS that allows for this to happen by whitelisting all mini-pci cards by going to forum.thinkpads.com and checking under the appropriate thread. Only then you will be able to install the 5300 or 6300 (although, you will need a bracket/adapter for this model in order to make it into a full height mini-pci card since that is the new form factor (half-height)).

My setup is exactly this, a modified BIOS and a Intel 6300AGN card with the bracket/adapter in order to fit the card in completely. The DPC latency issue has dissappeared, except for when I power off the lid while music is playing using FN+F3 and move the mouse or keyboard to turn it back on, music skips and the DCP Latency Checker SPIKES completely, stutterring the music for about 3 seconds then resumes. This never happened with the 4965AGN card. This holds true even after a complete reformat and reinstall and I am using the 6300AGN adapter direct from IBM/Lenovo. INTEL, PLEASE LOOK INTO THIS ISSUE FOR THE 6300AGN ADAPTER!!

Hope this helps everyone else!

[idata]

Perfect! Just got the 5300 from Amazon. I'll make the BIOS changes you suggest and try again.

[idata]

@Kamika007z:

"except for when I power off the lid while music is playing using FN+F3 and move the mouse or keyboard to turn it back on, music skips and the DCP Latency Checker SPIKES completely, stutterring the music for about 3 seconds then resumes. This never happened with the 4965AGN card."

In my case on T61 with 4965AGN I have not only audio stuttering but a system stuttering in such situation! So at the same time: high DPC latency spikes, audio stuttering and mouse cursor stuttering as well... System just chokes itself. So it doesn't look like caused by WiFi adapter.

[idata]

Hello everyone,

today I've had some time to do some further testings with the latest driver release from Intel Homepage version 13.4.0.139

WLAN-Driver: 13.4.0.139 (07.10.2010)

LAN-Driver: 9.13.41.0 (26.03.2010)

Laptop: Lenovo T61 8889-2BG

Memory = 4 GB

Graphic Adapter: Nvidia Quadro NVS 140M with latest driver from Lenovo Website (186.94)

Tests done: Disable 4965AGN driver - DPC spikes disappear, re-enable and DPC spikes reappear every 10 seconds.

What I don't understand is, why the problem is not mentioned under the "Known Issues" here: http://downloadmirror.intel.com/19514/eng/relnotes.htm# issues2 http://downloadmirror.intel.com/19514/eng/relnotes.htm# issues2

On 16.11.2010 IIlenek from Intel Customer Support mentioned, that Intel developer are working to fix the problem for Intel® Wireless WiFi Link 4965AGN adapters as did it for 5000 and 6000 series adapters, the version above is dated to the 07.10.2010 so that the driver is older than the posting.

@ IIlenek

Another posting here says that Intel® Wireless WiFi Link 4965AGN is "legacy" hardware now. Is there still a chance to get driver with a fix or are we at a loss? If I understand the informations on Intel Homepage correctly Windows 7 64 Bit is still a supported operating system for this chip. Please tell us what we could provide for additional informations. I'm a software engineer, too and from my point of view it cannot be so difficult to fix within over 2 years.

Today (22.02.2011) I did some further testings:

- setting the power mixer of NV GPU in registry to off as mentioned in Lenovo Forum (http://forums.lenovo.com/t5/T61-and-prior-T-series-ThinkPad/Audio-stutter-on-T61p/td-p/43413/page/45 http://forums.lenovo.com/t5/T61-and-prior-T-series-ThinkPad/Audio-stutter-on-T61p/td-p/43413/page/45) doesn't help. I tried as well different configurations of the registry key "PerfLevelSrc" (3322 and 2222).

http://imgur.com/oos1Q http://imgur.com/oos1Q

- I analysed the GPU clock using GPU-Z. There is no difference if GPU is running with 169MHz or 400MHz clock speed

- When disabling the WLAN adapter the DPC's stop. The screenshot shows the last yellow spike and the big red spike is the point when the adapter is disabled in hardware control center:

http://imgur.com/FAHxk http://imgur.com/FAHxk

Update (23.02.2011) installation of Windows 7 SP1:

- installing the service pack 1 for Windows 7 64bit does not fix the problem.

Kind Regards

KingTutt

[idata]

Well done now the latest driver (13.4.0.0) doesn't even work after suspend or resume resulting in limited connectivity or empty WLAN network list. Definnetly if I were one of those replacing this WLAN card I would go with another manufacturer like Broadcom or Atheros as they are focused on wireless products and may give at least a base support.

[idata]

Yes it is frustrating that apparently the Intel engineers still haven't solved this for Windows 7, 64 bit. Perhaps there too few of us users to make it worth the time and effort to fix since this is now legacy hardware. However, there are still a number of these cards still in service (as evidenced by this thread), and so I'm sure Intel has tried to fix it but failed. I'm sure that with the 'Centrino' label, Intel wants to be a major player in WiFi technology; but it does make it diffulcult for some of us users if they can't maintain their drivers as well as other vendors.

Good suggestion to try Broadcom or Atheros products.I'll check with Lenovo support to make sure that one of their WiFi cards are "approved" in the most recent BIOS for my T61p machine. Otherwise (like the newer Intel cards), my machine may not boot up if it doesn't see the Broadcom or Atheros cards on an approved list of network adapters.