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LDT/FSB Frequency Ratio's Affect On Temperature

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I just built another computer with the following specs:


DFI Lanparty UT NF3 250Gb

Sempron 2800+ Palermo

2x512 Corsair CMX512-3200C2 (slots 1 & 3)


Antec Smartpower 350


FSB Bus Frequency - 325

AGP Bus Frequency - 67mhz

Clock Spread Spectrum - Disabled

LDT Downstream Width - Auto

LDT Upstream Width - Auto

LDT/FSB Frequency - Auto

CPU/FSB Frequency Ratio - 8x



CPU VID Control - 1.325v

CPU VID Special Control - Above VID * 123%

Chip Set Voltage Control - 1.70v

AGP Voltage Control - 1.60v

DRAM Voltage Control - 2.7v


The overclocking guide says the following regarding LDT/FSB Frequency Ratio:


The only thing to keep in mind is that the stock HTT for a socket 754 is 1600 and for socket 939 its 2000.. And when overclocking your FSB Bus Frequency you want to lower the LDT multi to keep the HTT within a acceptable range.. (Socket 754=1200-1800 and Socket 939=Around 2000)

When I first overclocked the computer, I set the ratio to 2.5x. At my FSB frequency of 325, this makes the HTT 1624, an acceptable range. My CPU temperature was 29C at idle.


I was able to run Prime95 for 16 hours with no problems. However, SuperPi would fail at 1M or more. I then upped the LDT/FSB frequency ratio to 3x making the HTT 1950. Even though this was high, the computer was still stable and I could now run SuperPi. However, I noticed my CPU temperature at idle had increased to 38C.


I finally changed the LDT/FSB frequency ratio to auto and rebooted. The system is still stable, SuperPi now runs, and the temperature is down to 30C at idle.


What is my HTT if the LDT/FSB frequency ratio is auto? Why does this affect the CPU temperature?

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What is my HTT if the LDT/FSB frequency ratio is auto?


I would assume that the auto may = 2 LDT/FSB. At 2, your data rate =1300. I have found on my Clawhammer, any HTT data rate >1600 is unstable. As far as temps, I would hazard a guess that at a higher HTT data rate, your cpu is pushing very hard and the result is heat. I've not spent a ton of time looking at temps vs HTT data rate. I just played with my overclocks until I got a data rate as close as possible to 1600, while trying to get my RAM fsb and cpu cycles as high as possible.

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