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CPU temps/Chas temps high

Discussion in 'Overclocking' started by Phil, Squid-in-Training, Dec 12, 2004.

  1. When you guys say that you get 35C/45C temps on your procs, are you running
    your comps out in the open without a case?

    I've got mine enclosed in a case, with a Thermaltake Volcano 5, and three
    case fans (one in front blowing in, one in back blowing out, one blowing
    inside the case from front to back) and my temps are regularly in the low
    50's idle, and up to 69 load.

    I have a Soyo Dragon Plus SY-KT600 v1.0, XP 2200+ T-bred. The proc is
    properly thermal-pasted and set with no overhangs. I see a jump of about
    10C when I oc from 133MHz to 155MHz, and the computer used to shut itself
    down after 30 minutes in Prime95 until I turned off the thermal protection
    in the BIOS.

    Thing is, I opened up my case, turned on a table fan, and blew it directly
    into the case, and my chassis temps went from around 40 to 32 relatively
    quickly, so I know it's registering, but I'm not sure if the computer's just
    reporting hot and I don't know it, or if there's really a problem somewhere.
    My room is definitely not at 32, but I guess 12 degrees above room temp
    (20C) isn't out of the question.

    Does this seem like a mobo reporting issue, or is the damn thing actually
    that hot?
     
    Phil, Squid-in-Training, Dec 12, 2004
    #1
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  2. If the motherboard sensor is anywhere near anything that gets hot, and lots
    of components on recent motherboards may get VERY hot, then it will give
    some strange reading for 'in case ambient' 'system' temperature - I have a
    little 'Radio Spares' InfraRed remote sensing thermometer that's useful for
    picking up what temp's of components actually are without having to touch
    stuff. It's reasonably accurate I think - I have no calibration chart for it
    but it does read reasonably close at the melting point of ice and the
    boiling point of water. Any reasonably well ventilated system shouldn't
    actually be any 12C above room temperature: The one system that is sitting
    out in the open air here is registering 14C but that's reading rather low as
    it's more like 20C in here right now. the other 3 are reading 21 to 27C,
    quite a wide range coming from the same motherboard (NF7) and all in very
    similar cases but those little thermistors are nothing like accurate, so I
    don't mind a 6C spread too much - 3 systems, 1C to 7C above room ambient.
    All have 2x80mm inlet case fans , 2x80mm exhaust, including the PSU fan. All
    my CPUs bar 1 are watercooled with their radiators outside the case - the
    one air-cooled CPU is a TbredB 2400+ currently running at 10.5 x200 for
    2.1GHz (Lousy 5% O/C, bleagh.) at 45~50C that one has always run quite hot -
    the 0.13nm Tbred is a tiny weeny little scrap of glass that has one heck of
    a lot of power running through it..! That particular TbredB 2400+ maxed out
    at only 11x205 for 2.25GHz under a watercooled 220W Peltier way back shortly
    after I bought it (Nov 1st 2002) - luckily the 1.6Vcore & then 1.5Vcore
    spec' Tbred B 1700+ s rolled out late the next spring and they're magic
    overclockers - I have 3 of the 1.5Vcore version still running either at or
    approaching 2.4GHz plain watercooled & all at 1.8Vcore. The Barton XP-Ms are
    great overclockers but not as much bang-for-the-buck as those 1.5Vcore Tbred
    B 1700+s...
     
    Nick M V Salmon, Dec 12, 2004
    #2
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  3. Phil, Squid-in-Training

    Thomas Guest

    (snip)

    Well, I have had similar experiences with an AMD Athlon 1200. I got is
    cheaply; exchanged it for a Duron 600. The Athlon had a chipped core, and
    the PC would crash if the temp went above 55°C.

    I had an okay ventilated case, but still I'd get many crashes if i clocked
    the cpu to 1200 MHz. I had to underclock it to 1133 to keep it working.

    So, i decided to cut a hole in the side of my case, and equip it with a 92
    mm fan. I placed it so it would blow on the area where the CPU/GPU were
    located.

    This dramatically lowered my CPU temp! I could now clock the CPU to 1400,
    and still not see temps above 50°C!

    I still use the same computer case, but it;'s running my P4C 2.6, with
    watercooling :) All my fans are at 7V, and if i hadnt bought this 10k rpm
    harddisk, it'd be nearly silent :) Temp for the CPU is max 42 degrees. (My
    PC is next to the central heating radiator)

    enjoy,

    Thomas

    PS If you want to check out my WC setup, surf to www.tvdh.tk , and select
    computer --> main PC.
     
    Thomas, Dec 12, 2004
    #3
  4. and my chassis temps went from around 40 to 32 relatively quickly

    For both Intel & AMD chips...
    o CPU-Cooler intake fan should be below 38oC
    ---- ideally you want it around 32oC
    o If the case temperature is 40oC you need to improve airflow
    ---- that need not be via adding more fans
    ---- it may simply be via reducing case resistance

    Every enclosure has resistance to airflow - PCs especially :)
    o Exhaust & Intake fan grills are key airflow obstructions
    ---- ideally they should be round-wire-grills -- flow 89-91% free air
    ---- conversely punched case grills are poor -- flow 45-55% free air
    ---- 84% of a case airflow obstruction is the grills - and adds noise
    o Case fans exhaust only what they can draw in
    ---- airflow is subject to the lowest common denominator
    ---- as a rule that is the hole in the front intake plastic fascia
    ---- typically 3"x1" that is less than half the area of just 1x 80mm fan
    o CPU-Coolers recirculated their heated air until case fans remove it
    ---- so ideally an exhaust fan should sit behind the CPU
    ---- there should be minimal obstruction of the CPU-cooler intake

    Motherboard temperatures can be miss-reported, some checks:
    o Verify what temp your HD reports - via S.M.A.R.T. utils
    ---- you want this as low as practical re HD life
    o Verify the case temperature as best you can
    ---- typically the HD temp can give a general guide

    Removing the side from a case and finding temperatures drop is
    indicative of insufficient exhaust airflow (due to airflow obstruction,
    not necessarily due to insufficient fans) or CPU-cooler recirculating air.

    Some coolers are better than others:
    o Thermal mass, area & general design varies greatly
    o Blow-through coolers recirculate less air than Impingement coolers
    ---- blow-through coolers like a Zalman flower or to a lesser extent SLK
    ---- impingement coolers like a traditional AMD/Intel heatsink design
    o Impingement coolers recirculate 40-70% of their own air
    ---- so they require more airflow/noise to compensate

    Moulding a duct to get cool air direct to the CPU-cooler intake helps,
    however change 1 variable at a time - don't throw # fans at a solution.

    If you overclock a machine you have to uprate the heatsink as a rule,
    otherwise you may need disproportionately more airflow to compensate.
    Playing with voltage is important both re stability & thermal output.

    Check temps, reported temps can vary by +/- 10%, sometimes even more.
    That can be to your favour or against it of course, HD temps a good check.
     
    Dorothy Bradbury, Dec 13, 2004
    #4
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