CPU temps, USB usage

[7X7-800]

I have noticed certain USB devices causing a rise in cpu temps when plugged in on my Abit AV8. I have read an article referencing MS Knowledge Base Article KB918005. The article I was reading was talking specifically about CoreDuo processors but I was wondering if it might also apply to my situation.

[ozzy72]

What are your system specs and what device is causing the temperature rise?

[7X7-800]

Computer Specs: Enermax Noisetaker 2 600W
Abit AV8 Bios 27
Opteron 185 @2.9Ghz
Zalman CNPS9500 LED
Diamond X1950Pro Agp @621/740 w/
Arctic Cooling NV 5 Rev.3
2Gb OCZ Gold PC4000
2 74 GB WD Raptors, Raid 0
Plextor PX-750A
Creative Soundblaster Audigy 2 ZS
Logitech THX Z-5300e 5.1 speakers
Hauppauge WinTV-Pvr_150MCE
Samsung 245BW
Logitech Extreme 3D Pro
TrackIR 4
XP Pro SP2
FSX W/ Acceleration
LINKSKEY LDV-DM702AUSK (KVM Switch)
Canon CanoScan LIDE90 USB Interface Flatbed Scanner


Note cpu is overclocked.

Cpu temperatures as reported by various monitoring software (Abit Guru,

HWMonitor, PC Wizard 2008 run +12F above ambeint at startup.

Cpu temps normally reported around 93F @ 68F ambeint.

I initially noticed that plugging in the scanner (USB) (I don't normally have

it plugged in) caused the cpu temps to rise to approximately 125F. Next I

noticed that turning on my TrackIR (again USB) caused the same result. Lastly

after hooking up a new KVM switch(also USB)I noticed the same issue. At this

point I started looking into the matter more closely as the KVM is plugged in

all the time and I am sensitive to temperatures due to the overclocking.


After doing some online searching I ran accross the following forum

discusion from someone with the same issue:


http://www.lfsforum.net/showthread.php?t=5001

Post #15 offers a link to the following article which is more concerned with

notebook battery life with some usb devices, but the idea that my problem

could be caused by the same underlying factors seemed plausible enough for me

to take a deep breath and try the suggested registry edit.

Anandtech article wtih registry tweak:
http://www.anandtech.com/mobile/showdoc.aspx?i=2693&p=1


After applying the registry tweak my cpu temperature readings returned to

nearly normal. They are sometimes one or two degrees higher than before but

nothing major.

Maybe this can help someone else. Or perhaps I am just the last to know.

[7X7-800]

Update:

After applying XP SP RC2 it appears that the registry tweak previously mentioned no longer works. The entry is still in the registry but cpu temps have gone back up. Removing the Service Pack returns all to the previous state.

As far as the original post goes, I guess I would like to hear from anyone who is knowledgable in these matters (uh... NickN maybe) as I'm wondering if it might be affecting some people unwares and it appears to be an easy way to reduce CPU temps.

[NickN]

Its simple

USB applies a CPU load and if you are clocking you will see than load in temps

Every device draws more and more

I use a powered USB hub and take all that load off the system, even so... USB still requires CPU cycles and it seems to me if the temp is an issue you need to upgrade your HSF or reduce the clock

[7X7-800]

Then why would a simple registry edit apparently solve the problem?

Mind you I don't have the background you do so maybe I'm out of my depth here, but my understanding of the original articles on this matter was that it related to proccesor C-states and usb polling.

This particular subject is certainly not of earthshaking importance but it has piqued my interest and I can be very retentive when I'm looking for info, and it is often hard to find good brains to pick.

As always, I am grateful for any input.

[NickN]

First of all.. what patch are we talking about here.. post a link to it

2nd, I dont care what the patch does or how it changes polling, I would still not plug 3-5 devices into MB ports and use them. I would use a powered USB hub to get rid of the multiple CPU cycles being wasted by the system, patch or not, and allow the hub to absorb that load down to one signal.

[7X7-800]

See Reply #2, Jan 18 in this thread. I posted two links. They should be read in order.

[NickN]

See Reply #2, Jan 18 in this thread. I posted two links. They should be read in order.

1. Read SladiVadi's response in the first link... he has the right answer as simplistic as it is

2. That is a 2 year old article and since then the issuw was addressed in the proc, the motherboards and by MS

3. A8V is an old platform and the issue they are discussing has little to do with your processor or system although some of it can be influencing what you are seeing.


I would use a hub and forget patches or reg hacks unless it was offered as an OFFICIAL update from MS for your system. You are seeing exactly what SladiVadi said and especially overclocked you are seeing the result of it

[7X7-800]

Okay. I'll try out a hub. Thanks for your input.

[congo]

How does a hub save cpu cycles? I know it will supply power but I had no idea it was involved in logic .... other than routing each device's I/O....

[7X7-800]

FWIW I tried using a powered USB hub and it made no difference.

[NickN]

Its simple

USB applies a CPU load and if you are clocking you will see than load in temps

Every device draws more and more

I use a powered USB hub and take all that load off the system, even so... USB still requires CPU cycles and it seems to me if the temp is an issue you need to upgrade your HSF or reduce the clock

In other words the powered hub removes the I/O and system STRAIN issues brought on by multiple port USB devices.. in that you are VASTLY better off for smooth system operation using a powered hub and getting things down to one logical port. The system will run smoother under heavy load applications with multiple devices attached.

None the less, you are overclocked.. USB is exactly what was stated above, a CPU hog, and, your cooling solution is not enough to offset the loads the clock and USB are placing on the core.

All things stated were completely true and correct. If you are looking to A: make a CPU cooler and did not care about B: how efficient USB was with the system, the solution was to drop the clock, or, improve you CPU/Tower cooling.

[Brett_Henderson]

How does a hub save cpu cycles? I know it will supply power but I had no idea it was involved in logic .... other than routing each device's I/O....

This confuses me, too...

[NickN]

How does a hub save cpu cycles? I know it will supply power but I had no idea it was involved in logic .... other than routing each device's I/O....

This confuses me, too...