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Upgrade Bios = 15 degree cpu temp drop PLZ EXPLAIN

  • CPUs
  • BIOS
Last response: in CPUs
February 19, 2009 5:15:28 AM

System: Striker II extreme 790i ultra - q9550 @ 2.83 (stock) - stock heatsink - 4GB ddr3 1333 - 9800gx2 - cosmos s case (stock cooling)

Context: got system 6 months ago, had what i thought to be cpu temperature problems (60-65C load, rare 40C idle(mid 40s usually)). Read up in forums across the net and concluded i couldnt expect anything less with stock cooler and quad core.

For the longest time, I kind of gave up on the whole heat issue and decided it was in fact normal.

I just update my bios to the most recent version (from stock 0402 to 1104) and something extremely mysterious went down:
after the bios flash, I immediately opened everest to make sure all systems were stable (temps, fans ect.), and my jaw just dropped:

Temperatures (right after windows vista 64 load) were jumping between 38C and 45C!!!! Normaly they would be between 59C and 64C

I trippled checked with pc probe and ai suite and everything checked out.

I am now running full throttle at 45C MAX with no performance change, even maybe increase.

What happenned? is this normal?

Is my new bios right? is it just a buggy reading? was my old bios wrong? did the temperature actualy change?

Thank you all for your feedback
ne and all greatly appreciated

More about : upgrade bios degree cpu temp drop plz explain

February 19, 2009 7:25:17 AM

If the original BIOS did not ID the CPU correctly you may have been giving too much voltage. Latest BIOS is probably giving correct value.

a b à CPUs
February 19, 2009 7:28:21 AM

The temp sensor information might be more accurate?

Or perhaps your in Winter and the ambient temperature is lower?
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February 19, 2009 7:46:50 AM

lw, as your earlier BIOS dates to around the time of the q9550's introduction, I bet it didn't have the updated calibration information for the q9550's internal thermal sensors.
Assuming you are referring to a single overall CPU temp rather than temps for the individual cores, the reported temp value relies on a CPU-specific data table in the BIOS to convert measured readings into temperatures, and thus depends on your BIOS having the correct calibration info for your specific CPU.
The digital temp sensors in each CPU core on Intel chips provide direct digital readings, so you should go and compare your overall BIOS-reported CPU temp with the individual core temps that programs such as "coretemp" provide.
a b à CPUs
February 19, 2009 7:52:13 AM

Yes, wasn't the forum abuzz with inaccurate temps on the 45nm C2's?
February 19, 2009 8:02:18 AM

Yes, and that was for the digital (per-core) sensors -- sometimes, you can't win either way!
a c 309 à CPUs
February 19, 2009 3:41:04 PM


The on-die analog thermal diode from which CPU temperature is sampled is converted to a digital value by the super I/O chip on the motherboard, and is then calibrated in BIOS to processor specific tables, as Mondoman has explained. As BIOS programmers must code all socket 775 variants into each update, it's not uncommon for mistakes to show up, whether subtle or glaringly obvious.

Since "canned" values are seldom accurate, it's always prudent to calibrate your temperatures. If you'd like to learn how, then check out the Core 2 Quad and Duo Temperature Guide:

Comp :sol: 
a b à CPUs
February 20, 2009 7:49:59 PM

Comp saves the day!