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UndervoLting athLon II x3 455

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June 28, 2012 11:05:27 PM

Hello,

Just got a question, is it harmful to undervolt athlon II x3 455 @ 1.475v as CPU voltage and 1.464v as Vcore?

another thing is that, why is prime95 has different results when it come to tests done on different CPUs? i ran prime95 for 1 hour and 4 mins with 1.4v as CPU voltage and 1.36v+ as Vcore (autogenerated by mobo when i change it to 1.4v) and i got 48, 43 and 42 respectively so there, after that, i ran prime95 again with 1.475v as CPU voltage and 1.464v as Vcore and i got different results again. Can someone explain if this is normal and also normal to undervolt the CPU voltage because i tried it with 1.38v as CPU voltage with 1.356 as Vcore and run prime95 for 1 hour and 4 minutes however, what i've noticed is that "CPU 2" has now lesser iterations with from i can recall is around "8" compared to CPU1 and CPU3 with "12 or 13" after prime95 said it "passed". please help me understand all of these results. thanks!

btw, i'm planning to do a test with 1.37v for CPU voltage (not sure yet what's the Vcore) is this ok?

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June 29, 2012 2:02:53 AM

cReed_eRos said:
Hello,

Just got a question, is it harmful to undervolt athlon II x3 455 @ 1.475v as CPU voltage and 1.464v as Vcore?

another thing is that, why is prime95 has different results when it come to tests done on different CPUs? i ran prime95 for 1 hour and 4 mins with 1.4v as CPU voltage and 1.36v+ as Vcore (autogenerated by mobo when i change it to 1.4v) and i got 48, 43 and 42 respectively so there, after that, i ran prime95 again with 1.475v as CPU voltage and 1.464v as Vcore and i got different results again. Can someone explain if this is normal and also normal to undervolt the CPU voltage because i tried it with 1.38v as CPU voltage with 1.356 as Vcore and run prime95 for 1 hour and 4 minutes however, what i've noticed is that "CPU 2" has now lesser iterations with from i can recall is around "8" compared to CPU1 and CPU3 with "12 or 13" after prime95 said it "passed". please help me understand all of these results. thanks!

btw, i'm planning to do a test with 1.37v for CPU voltage (not sure yet what's the Vcore) is this ok?


the slight undervoltage your are doing shouldnt really hurt anything, but will hamper your performance. the Voltage is set by the manufacturer generally for the lowest stable voltage at full CPU performance (they scale all the CPU factors for this ie how many cores, stepping, efficency, mhz, voltage amperage etc. generally it comes out to around 1.35-1.5V. keep in mind that if your voltage is set by default to 1.5 V then dropping it to 1.4 volts may end up that the CPU does not having enough power to run all full speed or even power up all the cores. this is where your prime is seeing the different results. take for instance a Pentium 620 and 620T they are the Same processor with all the same identifiers and everything under CPUID but by dropping the frequency 400Mhz they were able to drop the TDP to 35W ,more then likely drop voltages as well.

Pentium 620 (2.6Ghz @65W)
http://www.cpu-world.com/CPUs/Pentium_Dual-Core/Intel-P...

Pentium 620T (2.2Ghz@35W)
http://www.cpu-world.com/CPUs/Pentium_Dual-Core/Intel-P...
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June 29, 2012 2:04:54 AM

if you planning on leaving it at lowered voltages i would lower your clockspeed as well. i personally have not tried that as normally i overvolt for overclocking not under clocking.
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June 29, 2012 3:03:53 AM

i see your point..so it's best to leave it as it is then? that Vcore was auto-generated by the BIOS when i opted to use "load default setup"
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June 29, 2012 3:41:47 AM

Undervolting can be critical to an oc in some situations. I have a 2.13ghz L5518 quad and with the stock voltage I was hardly able to get to 2.3ghz before my temps were at 80c. I found the lowest voltage my cpu needed and now I am at 3ghz with temps hardly getting above 70c.
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June 29, 2012 3:47:52 AM

i am trying to undervolt my system because my temp is a bit high @ 58-61C @ full load...actually i tried undervolting it to 1.4V (CPU Voltage and Vcore: 1.39) and my max temp was 57C. don't know if that helps but i'm not OCing my system...not sure if this board is capable of OC
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June 29, 2012 5:32:57 AM

rio747 said:
Undervolting can be critical to an oc in some situations. I have a 2.13ghz L5518 quad and with the stock voltage I was hardly able to get to 2.3ghz before my temps were at 80c. I found the lowest voltage my cpu needed and now I am at 3ghz with temps hardly getting above 70c.


is that on a Stock Cooler? i have never had this happen at max overclocking... highest ive seen is 70C
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July 6, 2012 12:24:08 AM

Best answer selected by cReed_eRos.
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