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PCI eXpress Frequency


CrashBFH

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Darn good question that I can't really answer. I run mine at 102, was having some stability problems during overclocking so decided to give it a whirl. Mysteriously my stability problems went away. So either I have a gremlin in my machine or changing that setting actually worked. I've left it that way ever since.

 

However, if any of the pros in here actually know how it affects performance and stability I'd love an explanation.

 

One point though, it seems that more people leave theirs at the default of 100 than those that change it.

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I've never even tried changing it...beats me. Some do indeed claim that it brings their system more stability, so if you're having some issues maybe bump it up a notch and see what happens.

 

Do you know if this helped video-related stability issues or cpu-memory issues?

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Well I kinda think my rig shot the whole dont exceed 102 thing outta the water. I actually gained a few points in 3D Mark 05 by playing with it and found my sweet spot to be 105. I ended up with a Sandiego 3700 and a single 7800GT scoreing 9176 in 3D Mark 05 so I am sur eit has some overall effect on the system. My Score on 3D Mark 06 with the same 7800GT but an X2 3800 came in at 4955.

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PCI-E freq. is the same as the old AGP freq.

 

Where as the AGP bus use to be clocked at 66 mhz the new PCI-E bus is clocked at 100 mhz.

 

So increasing the PCI-E freq. simply increases the bandwidth (the amount of data that can be transfered in a given time).

 

It has been proven time and time again that even at 8x the PCI-E bus is not saturated let alone at 16x.

 

So bottom line increasing this freq. will do nothing for you.

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PCI-E freq. is the same as the old AGP freq.

 

Where as the AGP bus use to be clocked at 66 mhz the new PCI-E bus is clocked at 100 mhz.

 

So increasing the PCI-E freq. simply increases the bandwidth (the amount of data that can be transfered in a given time).

 

It has been proven time and time again that even at 8x the PCI-E bus is not saturated let alone at 16x.

 

So bottom line increasing this freq. will do nothing for you.

 

There is a difference the between simple number of cars allowed on the highway and the speed (time) at which those cars are travelling the length of the highway....saturation and speed are not the same....

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It's pretty simple actually - Not all PCI-E locks are completely stable. Changing to 101 or 102 simply re-inforces the Lock at that frequency - your're basically taking it off auto.

 

Just like it was often a good idea to set AGP to 67mhz - it helped when the lock wasn't stable.

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