nForce2 chipset - needs to be *very* cool for SPDIF to work?

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inti
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nForce2 chipset - needs to be *very* cool for SPDIF to work?

Post by inti » Tue Jul 19, 2005 3:17 am

I'd be interested to know if anybody else has this problem ...

I have an nForce2 motherboard (Asus A7N8X-E Deluxe) in my HTPC. It seems that the audio is very fussy about the chipset temperature. If the chipset heatsink is even warm to the touch (35 degrees C?) the audio system will not boot properly so there is no Soundstorm driver and no multi-channel output. SPDIF audio output (direct digital output for DD5.1 audio on DVDs) is the most temperamental of all, if the chipset warms up slightly while the PC is on then you can sometimes lose SPDIF output after a few minutes.

Everything else in the system is fine; it is Prime95 stable.

Here's the system in more detail:
* Sonata case - lower front bezel and filter completely removed; 'Antec' holes not blocked; 120mm front intake fan, 120mm stock case fan, Seasonic 430W PSU with 120mm fan.
* Athlon XP-M 2500+ at stock 1.45V; 1833Mhz
* 166MHz bus
* 1GB PC3200 RAM (Geil; CAS 2.5; blue heatspreaders)
* ATI Radeon 9550, passively cooled with Zalman 'C' type cooler

The system does not draw heavy power - the Seasonic PSU fan is normally at 890rpm. In wintertime, both the case fans are at 5V and the system is very stable. But in these summer temperatures (22-30 degreees C here in recent weeks) I'm having real problems, even with the case fans on 12V (hardly a silent solution) - if the chipset rises just 5 degrees above ambient then I get no audio.

I have added a 40mm fan to the chipset heatsink but that does not help much when a mere 5 degrees above ambient is enough to cause a problem.

It seems to me like the motherboard design is not that great, as there is a cluster of the hottest components next to each other - the CPU heatsink is about 20mm away from the chipset heatsink, as is the rear of the passively-cooled graphics card, as is the RAM. It must be difficult for the chipset to get cool air at all.

(Some great pictures of the layout can be seen in this review at HardOCP:
http://www.hardocp.com/article.html?art=NTc3)


I'd be interested in any comments:

(1) Is the audio on the nForce2 (specifically the SPDIF) known to be super temperature-sensitive?
(2) Could it be a bad thermal connection between the chipset and its heatsink? If so, any tips for how to solve that, as I believe the chipset heatsink is not supposed to be 'user-removable'.
(3) Does it sound like my motherboard is faulty? I don't really want to return it as that would leave me with no PC for several weeks.
(4) Any recommendations for better chipset cooling - perhaps a way to duct cool air directly to it?

Thanks ...

inti
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Joined: Thu Feb 10, 2005 7:09 am
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Post by inti » Tue Jul 19, 2005 3:53 am

For reference, here are three threads about replacement heatsinks for nForce4:
http://forums.silentpcreview.com/viewtopic.php?t=23369
http://forums.silentpcreview.com/viewtopic.php?t=19902
http://forums.silentpcreview.com/viewtopic.php?t=23233

and here is a thread about replacement heatsinks for nForce3:
http://forums.silentpcreview.com/viewtopic.php?t=17764

and for nForce2:
http://forums.silentpcreview.com/viewtopic.php?t=19333

Here is the "lapping" tutorial at nForcersHQ:
http://www.nforcershq.com/forum/4-vt239 ... c&start=30
(mainly aimed at the old nForce2 used in the Asus A7N8X, but also could be relevant to the nForce2 Ultra used in the A7N8X-E Deluxe although that is supposed to be a flatter northbridge to start with).

(Lapping and/or replacing the chipset heatsink is a last resort for me, as I would have to remove the motherboard from the case - no mobo tray :( - probably takes more than 2 hours to do that and put it all back together again.)

jamesm
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Location: California, USA

Post by jamesm » Tue Jul 19, 2005 9:04 am

I saw a SB live go for $0.01 on ebay (plus $7 shipping). You might consider picking one of those up.

wim
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Location: canberra, australia

Post by wim » Tue Jul 19, 2005 9:58 am

soundstorm is the best thing about a7n8x. to replace soundstorm with an SB live would be a crime.

(1) no. the APU is actually in the southbridge, which does not have a heatsink on it at all and barely gets warm to the touch. that chipset heatsink is on the northbridge!
(2) unsure...doubtful, because your chipset temperature is not hot (assuming you were measuring the temp with software, not just guessing by touch)
(3) yes :( i think you got a dodgy MCP-T
(4) i'm doubting insufficient cooling is the problem because a) the audio is in the MCP-T chip and b) the chipset can get a LOT hotter than that. mine routinely runs at about 46C idle and up to maybe 60C load, and always sits 5 to 10C above the cpu temps. this is using the stock passive cooling and never had any audio troubles like yours..

last but not least: doesn't sound like this is a silent computing issue at all, you would do better asking at nforcershq.

SebRad
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Post by SebRad » Tue Jul 19, 2005 10:24 am

Hi, I have an A7N8X Deluxe and have to confes to not using the onboard audio, but I don't have the gear to use a digital out anyway. At one stage I was having problems with the IDE controllers. Errors in Event Log and Optical drives would just lock up under heavy use (ripping). I'd read about about South bridge overheating with reguard to audio problems and as the IDE controllers are in the Southbridge I decided to put a heatsink on it. I used a 40x40mm Northbridge heatsink (w/out fan), fixed with a blob of super glue in each corner and thermal paste over the main. It's stuck on fine and gets pretty warm in use so I can only imaging how how it got before. I think it pretty much cured the IDE problems too.
Pic
Seb

inti
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Post by inti » Wed Jul 20, 2005 9:27 am

Thank you for those responses. I did look at getting a separate soundcard, but I like the nForce2 onboard audio a lot when it is working (the AC3 encoding ability is great as I only have a digital connection to my amp/speakers); also I would prefer to fix the problem at its source as I don't like the idea that part of my motherboard is failing.

I will try a heatsink on the Southbridge - thanks for that suggestion.

I guess it is just unfortunate that these boards were designed with hot components (i.e. northbridge and southbridge) right next to the hot video card - maybe video cards didn't get so hot when these boards were originally designed?

mshan
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Post by mshan » Wed Jul 20, 2005 9:36 am

I have an Asus A7N8X v2 Deluxe and ATI Radeon 9700 Pro in an Antec Sonata case and have never had any problems with onboard audio.

Search the archives at http://forums.pcper.com/forumdisplay.php?f=8 or post your question in that forum; Senor Panadero is an awesome AMD resource.

Kaizer
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Post by Kaizer » Wed Jul 20, 2005 10:00 pm

A while ago, someone posted a link to a thermal imaging test performed by bigbruin.com on the A7N8x DLX Rev. 1.04.

http://www.bigbruin.com/reviews/thermalimages/

The reviewer(s) did notice an extremely hot chip near the southbridge area http://www.bigbruin.com/reviews/thermal ... bridge.jpg

That chip was running at almost 100 C and its function is described below (Note, this paragraph is taken directly from the bigbruin.com's review page.):

"After a bit of research, it looks like the little "smoking" chip by the south bridge is the Chipset Voltage Regulator CM3708 (Thanks to the MJ Vdd mod at nForcersHQ) I wonder if its "just under boiling" temperature is part of many of the problems associated with this board. Could this be the Bios Death trigger? Maybe the Soundstorm noise maker? Who knows? I'm thinking one of the spikes from a Northbridge style sink glued on there might help." - bigbruin.com

In spite of the fact that the board reviewed is the Rev. 1.04 of the A7N8X Delux (not the E-version), the location of the CM3708 is the same for the Rev 1.04 and the E-delux (I've confirmed it from my E-delux board). So putting a heatsink on that chip may solve your problem.

I am only using the analog output on my A7N8XE-Dlx so I can't confirm the problem. Nevertheless, thanks for bring it up. I guess I'll have do some further investigations before dishing out the bucks for a set of 5.1 digital speakers.

inti
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Post by inti » Thu Jul 21, 2005 1:43 am

Aha (oho, a track in the snow).

Kaizer that is awesome information - thank you very much - what a great forum this is.

The idea that it is the overheated voltage regulator causing the problems would fit well with another symptom, which is that the availability of SPDIF seems to depend not only on temperature but also on the number of HDDs in the system - I have two system drives and anything from 0 to 4 extra HDDs in a caddy system run off a 4-port Promise SATA controller - sometimes I have to turn off all extra HDDs just to get SPDIF to boot. (The extra HDDs are SATA with staggered spin-up, and I have a good 430W Seasonic PSU, so I don't think it is a PSU issue as such - anyhow the symptoms are the same using the stock 380W Antec PSU with is top top quality in terms of voltage stability.)

Will try a few heatsinks and the "intiscope" thermal sensor (aka my finger) tonight, and report back.

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