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Much higher CPU temperature after switching to 2000 from XP

By Nate112233
Sep 20, 2005
  1. I am completely confused on this one.

    Pentium 4 2.4c HT w/ stock retail cooling

    I had previously been using Windows XP with this computer and had too much garbage installed so I decided to reformat and reload. I also decided to go back to Windows 2000 just because I seem to like it more.

    The whole time I was using Windows XP for a couple of years now atleast, my CPU idle temps were around 37 degrees celcius. I was pretty happy with this for stock cooling.

    I have always been using MBM to check my CPU temps.

    Now that I have installed Windows 2000 my idle temps have been around 52 degrees celcius. That is quite the jump. I know this is still in the allowed limits for this processor but I am completely confused on why this is like this. I checked to make sure there was not some process running in the task manager. The cpu % stays at 0 and the temperature will not drop below 50 at all. There was absolutly nothing changed with the hardware with the reformat and loading of Windows 2000.

    I checked the BIOS setup to see what the temperatures were going to there and they are normal like they used to be. After rebooting from the computer running Windows 2000 at 52 degrees celcius and then going into the BIOS setup. I can watch the temperature drop down into the 40's like it has always been at in the BIOS except it used to raise to the 40's and now its drops to the 40's. So the temperature in the BIOS setup is still the same. It is just the temperature while in Windows 2000.

    Has anyone had anything similar happen to them? This makes absolutly no sense to me.

    Thanks.

    The only thing that I could think of that could have been causing this was if ACPI was not working properly. I couldn't really find to check whether this is turned on or off but I can find it installed in the device manager and I am not having any problems shutting down the computer.



    I installed a program called CpuIdle Extreme and it is able to get my temperatures down to where they were with Windows XP. This is a shareware program that expires in 30 days though so this is not a real option for me. I don't want to have this thing on my task bar and let it use resources either. So, for some reason Windows 2000 is not able to let CPU idle like Windows XP does. Hopefully someone knows how to fix this one.

    Thanks.
     
  2. Blakhart

    Blakhart TS Rookie Posts: 353

    Hi

    What comes to mind here are a few diffs between xp and 2k.

    One of wich is a much improved ACPI in xp over 2k. This is the interface that controls power.
    Secondly is a much improved scheduler in xp. This decides what code gets run and when.
    Third would be native support for HT (not just SMP) in xp, an add-on in 2k. 2k has no real clue about HT, just SMP. SMP is not HT, think of HT as vestigial processors as the cache and pretty much everything else in the cpu core is fought over by the execution units in an HT cpu. SMP systems do not suffer from this. Oh yeah, HT = SMT = http://www.cs.washington.edu/research/smt/, . SMP = http://www.webopedia.com/TERM/S/SMP.html
    I also suspect that xp has a better APIC than the APIC implementation in 2k. APIC is not ACPI. It's the Advanced Programmable Interrupt Controller, handling all the interrupts, yo. ACPI = Advanced Configuration and Power Interface, responsible for putting stuff to sleep and whatnot..

    All of this can have a bearing on performance and heat generation in your system.
    I would only run xp on an HT system.
    And I do!! heh

    Here's another way of looking at the above: in a dual cpu system, or HT system, 2k uses, more or less, a fifo (first-in-first-out) algorithm for mem paging. This means that no matter how often you need a certain bit of data to be in memory, 2k will send it to disk/pagefile eventualy. Xp using the LRU (least-recently-used) algorithm will keep data in memory as long as it is often needed. Only paging when the data hasn't been used in quite a while. Funny that 2k uses the same paging algorithm as xp does when 2k runs on a single cpu system. Seems that making a virtual memory system for SMP/HT systems is kinda complicated.

    Ok I'll shut up now.
     
  3. Nate112233

    Nate112233 TS Rookie Topic Starter

    Thanks for the response. I didn't realize that Windows 2000 didn't support hyperthreading. I had just assumed it did. I turned off hyperthreading but the temps are still higher but not as bad. I guess I will be switching back to Windows XP after all.
     
  4. Blakhart

    Blakhart TS Rookie Posts: 353

    Hi
    I double checked on my diatribe and yeah xp does know the diff between HT and SMP. With an HT cpu, xp will only run threads that don't compete for resources within the cpu, maximizing performance and lowering latency.
    I think 2k on the other hand only knows SMP and so will shedule threads no matter if they flow smoothly or will contend for resources.

    My thoughts on the overall temp situation is that 2k's ACPI might be to blame here. Service packs can only do so much, and kernel changes are out of the question, I guess.
    Does the system show 100% cpu usage at all times? I have seen that too with 2k. It is caused by certain ACPI functions in 2k.

    :chef:


    Edit: straight from Intel, yo. http://support.intel.com/support/processors/sb/CS-017343.htm
     
  5. vegasgmc

    vegasgmc TechSpot Chancellor Posts: 1,377

    I dual boot XP and 2000 and my processor runs a few degrees warmer in 2000 but it has never caused any problems.
     
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