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Strange Heat Issue

F

Fiontar

Junior Member
Hi all,

I noticed something extremely odd today and was wondering if anyone has any thoughts or can verify a similar effect on their own systems. My rig is detailed in my profile below.

The odd thing I noticed today and verified with some testing is that when my USB 2.0 160 GB Seagate External Hard Drive is turned on, my CPU temp instantly rises 2C to 3C and stays at the elevated level, even though the HD isn't doing anything active and CPU usage shows no increase in Windows Task Manager.

Turn it on, heat goes up, touch nothing, stays steady, turn the external HD off, CPU temp drops back to normal.

With moderate External HD activity, the CPU temp increases another 4C on average, even though Task Manager shows very little CPU usage (1% to 4%)

Active use of the External Drive raises my CPU temps almost as much as playing WoW.

What is going on here?

Motherboard Temp doesn't show an immediate increase, although when the CPU is running4+C hotter, eventually the MB temp will rise a degree or two.

Is the USB 2.0 controler on the Athlon 64 die? Doesn't it seem odd that just plugging in the (self powered) external drive would increase CPU temps to that degree? My keyboard is a backlit USB (Saitek Eclipse) and plugging or unplugging it from the same bus or even the same port has zero impact on CPU temp.

I'm curious if anyone has any thoughts or can verify this effect with their own hardware. I also wonder if a PCI USB 2.0 add in card would bypass the USB 2.0 controler I am guessing is on the CPU, and thus decrease the temps?

The external drive is used almost exclusively for backups, so it's not a huge issue, but I find the temp rise to be very unexpected and would like to figure out why.
 
The USB controller is not on the CPU itself. It is on the southbridge. The only thing I could think of that would cause this is some sort of voltage fluctuation causing the thermistor to read incorrectly. Especially if it is an immediate change when there is a load on the USB interface. (Maybe check it with other USB devices, I imagine the drive is self-powered?)
 
Yeah, the drive is self powered. My keyboard is a non-self powered, backlit Saitek, which draws the power for the leds from the USB port and it has zero impact on CPU tempt if I plug it it or unplug it. My printer has been dead and in need of a replacement for a while now, so can't test with that.

I'm mid back up now, but when I'm done, I'll see if PC Probe reports any voltage fluctuations when I turn the external drive on or off.
 
No unusual fluctuations or change in average voltages reported by PC Probe when turning the external HDD on or off. The temp. change starts with in a few seconds of power on/off of the drive, it can take up to 3 minutes to stabalize.

Reported CPU temp w/o external HDD: 34C
Reported CPU temp W/ external HDD: 37C

This is with no load on the HDD and Task Manager showing no increase in overall CPU load.

It makes no logical sense, which is why it's bugging me so much! 🙂
 
Originally posted by: Brock123
does cpu utilization go up?
Click to expand...

Nope. No difference in CPU utilization.

I swapped in a new powersupply, (new Antec TP2 550 died after 3 days, was using a 450 temporarily until the replacement arrived, back to a new 550), it has made no difference with this problem.

CPU utilization is between 0% and 2% on one core, just firefox and explorer and the usual background processes. No drive activity. I just turned the external drive back on for the heck of it, CPU temp went from 32C to 36C in under 2 minutes.

I've tried plugging in to each of the 4 USB 2.0 ports on the back of my computer, same problem.

Voltages don't report any fluctuation or increase related to the external drive being on or off.

My southrbridge just has the default passive heatsink. I would suspect that the southbridge could be heating up and transfering that heat to other components, but the motherboard temp doesn't really change with the drive at idle, just the cpu temp.

I'm stumped.

If anyone has an external hard drive and the ability to monitor CPU temps, I would be interested to see if anyone else records a temp increase when the external drive is powered up.
 
Threads a little old, but I just found a fix for this problem the other day -- noticed temps increased when I hooked up my USB 2.0 drive to the computer as well.

I'm running an Athlon XP 3200+ and idle temps were 35 -37C. When I attached a USB 2.0 device the temps increased to 40 - 44C. After I added a new registry key my temps have stopped fluctuating and computer room is actually cooler (i.e. the only way to bring the idle temps back down was to reboot before so this thing was actually sucking a few watts).

This appears to be caused by the MS usb 2.0 bug that is causing decreased battery life in some laptops:

--------------------------------
"A Windows XP SP2-based portable computer uses its battery power more quickly than you expect when a USB 2.0 device is connected

View products that this article applies to.

Partner Only Article Article ID : 899179

Last Review : July 12, 2005

Revision : 1.0

Important: This article contains information about how to modify the registry. Make sure to back up the registry before you modify it. Make sure that you know how to restore the registry if a problem occurs. For more information about how to back up, restore, and modify the registry, click the following article number to view the article in the Microsoft Knowledge Base:

256986 (https://premier.microsoft.com/kb/256986/) Description of the Microsoft Windows registry


SYMPTOMS

Consider the following scenario. You install Microsoft Windows XP Service Pack 2 (SP2) on a portable computer. Then, you connect a USB 2.0 device to the computer. In this scenario, the computer uses its battery power more quickly than you expect.

CAUSE

Windows XP SP2 installs a USB 2.0 driver that initializes any connected USB device. However, the USB 2.0 driver leaves the asynchronous scheduler component continuously running. This problem causes continuous instances of memory access that prevent the computer from entering the deeper Advanced Configuration and Power Interface (ACPI) processor idle sleep states. These processor idle sleep states are also known as C states. For example, these include the C3 and C4 states. These sleep states are designed, in part, to save battery power. If an otherwise idle portable computer cannot enter or maintain the processor idle sleep states, the computer uses its battery power more quickly than you expect.

RESOLUTION

Warning: Serious problems might occur if you modify the registry incorrectly by using Registry Editor or by using another method. These problems might require that you reinstall your operating system. Microsoft cannot guarantee that these problems can be solved. Modify the registry at your own risk. To resolve this problem, add the EnIdleEndpointSupport entry to the USB registry key. To do this, follow these steps:
Click Start, click Run, type regedit, and then click OK.
Locate, and then click the following registry subkey:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Servic es\USB

Note: If the USB subkey does not exist, create it. To do this, follow these steps:
a. Select the Services key. On the Edit menu, point to New, and then click Key.
b. Type USB in the New Key #1 box to name the new key "USB."


Right-click USB, point to New, and then click DWORD Value.
In the New Value #1 box that appears, type EnIdleEndpointSupport, and then press ENTER.
Right-click EnIdleEndpointSupport, and then click Modify.
In the Value data box, type 1, leave the Hexadecimal option selected, and then click OK.
Quit Registry Editor.
STATUS

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

APPLIES TO

Microsoft Windows XP Service Pack 2, when used with:

Microsoft Windows XP Professional
Microsoft Windows XP Home Edition
----------------------------------------------------------------

 
"This appears to be caused by the MS usb 2.0 bug that is causing decreased battery life in some laptops"

Yep, that's my first thought. Do like the nice man says 🙂
 
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