"sending it in" wont help as there is no fix :) All same board have same problem :) We have to push lenovo to give us "replacement boards" with fixed problems...

 AUDIO  skips and SATA not able to run in sata II mode.. tubomemory lockups...ASP incompatibility with never hard drives = wont work with mine new 5400.6 seagate.... as lot of the machines have more than 1 year of warranty left... WE NEED LIST OF "working" FRU if they really exists...

Without a bad publicity there wont be any fix..

(who cares about some audio problems, it cost money and development for an outdated product....they think...)

hi mark

here's what i know about the audio stutter/latency issue

media types, all of the following are effected:

~ streaming media (internet radio)
~ compressed audio (mp3, aac, etc)
~ uncompressed audio (cda, wav, etc)
~ video files (mov, avi, wmv, etc)
~ local media (files, cd audio) and network sources shares

media players:

~ iTunes, Winamp, Windows Media Player, Media Center, VLC, etc

troubleshooting tools:

~ DPC Latency Checker to monitor Deferred Procedure Call activity
~ GPU-Z to monitor the Core Clock & Memory Clock

when using GPU-Z to monitor power state transitions, the Sensors tab must be selected (to view the GPU's clock state in real-time) and 'Continue refreshing this screen while in the background'  must also be enabled - because the Graphics Card tab only shows static values for the GPU clock frequency, and without background monitoring enabled, the core clock frequency transitions will not get updated (when another window/app has focus).

the latencies are less likely to occur when full motion video is being played or rendering 3D content, etc.  reason being, the GPU would then be constantly running at a higher power state (higher clock frequency), while it's rendering high-bandwidth video.  but, when GPU-load is low, it throttles back to a lower power state, accompanied by a corresponding DPC latency (and audio drop-out), at the exact moment of the power transition.  there are usually TWO latencies, always 30 seconds apart, each one occuring as the GPU transitions b/w one of its three power levels (475|275|169 MHz).

the DPC Latency Checker doesn't always catch the latency spike because the DPC test interval is fixed at 1 second (1000 microseconds); so if a GPU transition takes place when the DPC tool isn't 'watching', the latency spike doesn't get reported - BUT the audio drop-out still occurs and GPU-Z also indicates that the drop-out coincided with a GPU power transition (frequency change).

the audio drop-outs last anywhere from a brief 'stutter' to a full second or so of silence.  when the drop-out occurs, the media player(s) show that the source material is still playing, as evidenced by VU meter activity, but the audio gets cut-out for a brief moment.

so, in case i haven't stressed this enough already - the dropouts always occur at the very *same* moment that the GPU transitions b/w power states (frequency changes), without exception... on my system anyway.

one workaround that i found to be helpful is to prevent the GPU from transitioning b/w power states (fixed at max power), using the registy tweak i mentioned in post #74:

HKLM\SYSTEM\CurrentControlSet\Control\Video\{GUID unique to your system}\0000\PerfLevelSrc

that simple change has stopped the intermittent audio drop-outs, but i can still induce a (long) latency by launching the Nvidia Control Panel.

given what i've learned so far, i'm convinced the issue stems from a misbehaving display driver or the video hardware.  whatever the case, some event is taking place that intermittently halts DPC processing activity, and consequently, disrupts the flow of audio data.  so imo, Lenovo's techies should try troubleshooting the problem with DPC Latency Checker and GPU-Z, as i (and many others) have done.

if you'd like screen/video captures of what i'm talking about, let me know.

Excellent tools!!

(average about 1000)

but:

62221 microseconds :) really bad.. (but as sad not al spikes ar noted)... wil tr to figure out relation to it.

when changing GPU clock there are spikes around 2500microseconds..

report =  

Some device drivers on this machine behave bad and will probably cause drop-outs in real-time audio and/or video streams. To isolate the misbehaving driver use Device Manager and disable/re-enable various devices, one at a time. Try network and W-LAN adapters, modems, internal sound devices, USB host controllers, etc. ....

So I sent my t400 in and they replaced the motherboard and speakers and the stutter is gone.

but they also formatted my hard drive when i explicitly told them not to... so theres goes all my data. 

And they shipped to the wrong address so I had to wait an extra week to get it back.

go lenovo!

@ashenkin - "slow garbled sound?"  hmm, i'm not even sure what that is, nor where you got that idea.  anyway, as i've repeatedly said, the 'audio drop-outs' affecting my system coincide with the dpc latencies, ie, the audio cuts-out briefly, but there's NO distortion (garbled sound?).

hmm, maybe this will help... the dictionary defines:

stutter - to speak in such a way that the rhythm is interrupted by repetitions, blocks or spasms, or prolongations of sounds or syllables, sometimes accompanied by contortions of the face and body.

(oh yeah! there's definitely contortions in my face after the audio cuts-out... usually followed by a litany of swear words)

garbled - to mix up or distort to such an extent as to make misleading or incomprehensible; to scramble (a signal or message), as by erroneous encoding or faulty transmission.

(umm nope, that sounds more like audio distortion to me... and not what's happening on my system)

thus, the audio drop-outs affecting my system would be more accurately described as a 'stutter', i should think

@alunj - "they replaced the system board, which seems to have fixed the stutter"

pardon me, but what does seems mean? 

does the audio stutter (or not) after you got the machine back?

@kcrazy - ugh, well that good news... and bad.  good for you that your machine is now fixed... bad for the rest of us who still don't know wth is going wrong with our systems or what lenovo is doing about it... if anything??  i'm not liking the idea of having to return two brand new thinkpads to undergo major repairs (mainboard is probably as major as it gets).

anyway... way to go lenovo! :~\