[Ham-Computers] RE: Computer temperatures

[Hsu, Aaron (NBC Universal)]

These  MCH and ICH are terms created by Intel - they're acronyms for the "Memory Controller Hub" and the "I/O Controller Hub".  They're also known as the "sorthbridge" (MCH) and "southbridge (ICH).  Both chips combined form the basis of the motherboard.  MCH and ICH are usually sold as sets, but it's possible to combine different versions of MCH and ICH as long as they're interface compatible.  A common reason to do this is cost - it may be less expensive to use an older or slower ICH (or one from a different vendor) to make a "budget" motherboard.

The "northbridge" (MCH) is the chip that directly interfaces (connects) the CPU, RAM, and the "high speed" video interface (be it AGP or PCI-e x16).  It basically interfaces the "fastest" components on the systemboard.  Most northbridge chips run quite warm - averaging 40 to 60 degrees C.  That might even be higher if doing memory intensive tasks (including gaming where much data is flowing to the AGP/PCI-e slot).  On "enthusiast" motherboards (used by gamers and tweakers), there is often a large heatsink on the northbridge - some even have fans.

The "southbridge" ICH is the chip that interfaces to the MCH and adds I/O support.  An example of what's on a southbridge are "native" hard drive interfaces (SATA/PATA), PCI & PCI-e slots, USB controller, "legacy" I/O, audio interface, on-board video, etc.  Often, if the motherboard offers "additional" slots or hard drive connectors, the chip controlling those slots/connectors will be interfaced to the ICH - usually via PCI or PCI-e.  The southbridge runs slower than the northbridge, so it runs cooler and often doesn't have a heatsink.

There are several Windows utilities that will show the temps if the sensors are "available" (meaning there's a way to read their status).  One of the difficult things with these types of apps is the sheer number of "system health" chips out there - each one has a different programming interface (API).  So, each time a new motherboard comes out, if it uses a different system health monitor chip, the utilities need to be updated to support it.  Plus, each motherboard vendor might implement the chip differently, so that just complicates things.

Motherboard Monitor (MBM) was a popular app, but it's development was stopped a few years ago - probably due to the difficulty mentioned above.  I use SpeedFan (http://www.almico.com/speedfan.php), but this app is geared more towards fan management.  It's also a "tweakers" tool and requires some fiddling to get working properly - for example, it can detect fans and temperature sensors, but it doesn't know exactly where these are.  It just labels them as "Temp 1", "Temp 2", "Fan 1", "Fan 2", etc. and you need to relabel them yourself.  Also, the sensors themselves are simple A/D converters and any calibration might be programmed into the system BIOS - when you use something like SpeedFan, it doesn't use any BIOS calibration data, so you may need to configure that yourself or at least take that into consideration.  For example, most temp monitors (like SpeedFan) have been off by 10 degrees C with the Intel E8000 series CPU's.  This is because the API for the core thermal sensor changed.  Also, some motherboards have a CPU temp sensor - this usually reads lower than the on-chip "core temp" sensor.  Some programs use the motherboard sensor, some use the "core" sensor, and some might report both.  If it only reports one, it might list that as "CPU" - well, is that the motherboard sensor or the "core" sensor?  You get the idea.

Many motherboard vendors include a system monitoring tool with the motherboard (or downloadable).  These are programmed specifically for that vendor's products, so the temp and fan sensors are usually labeled correctly and any compensation is included.  However, these apps might also be buggy, bloated, or just plain butt ugly.

See if your motherboard vendor has a tool available to monitor system temps in Windows.  If not, give SpeedFan a shot.  As for dust build-up, take a can of compressed air (dust-off) and, using short 1 second bursts, "blow out" the CPU heatsink and fan.  Although you might not "see" much, you'll be surprised at how much has actually accumulated.  Better yet, if you know how, take the CPU fan off the CPU before using blowing it out.  If you do this though, you'll need to clean-off the old thermal material on the heat sink and CPU and use new material when you put the heatsink/fan back on.

73,

  - Aaron, NN6O


-----Original Message-----
Sent: Friday, July 25, 2008 9:14 AM
Subject: [Ham-Computers] Computer temperatures

Group,

In Setup on Intel and Intel based mother boards one of the screens displays several current operating termperatures.  One or two called Motherboard.  CPU or CPU Core.  On this year old Intel board, two more are called ICH and MCH.
  
The machine locked up sometime early this morning and again shortly after I rebooted it.  When I went into Setup, I found all of the temperatures to be say between 50 and 55C, and drifting down slightly as the complete side cover was off.  But one ID'd as ICH was at 88C.  Can anyone tell me what ICH is?  And for that matter, MCH?

I looked the board over but didn't find any large accumulation of dust buildup (which seems to have turned out to be why the previous system board was rebooting itself).

Robert & Susan Downs - Houston
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