Trying To Understand Overclocking

[muskyx1]

I have been playing around with my i7 920 system with 6Gigs of 1600 ddr3 ram for a few weeks now and I am impressed with how fast it encodes video using Nero. It converts video 2.6 to 3.5 times faster than an Athlon x2 6000+ 3.0Ghz that I have.

Now my inquiry is regarding over clocking. The i7 920 CPU rarely passes 70% usage in the task manager. I?ve been informed that with my high end ram and CPU, it?s likely the HDD is the bottleneck.

What I don?t understand is if the HDD is the limiting factor, why does encoding rate increase when I overclock.

 

[Duvie]

Actually it really shouldn't....Just because a process doesn't use all of the cores doesn't mean you are IO limited....It may very well be with the software and how will it is multithreaded....

If overclock increases and utiliz goes down...then think IO limits....

If overclock goes up and utiliz stays the same...I think it points to the softwares ability....

If I render my HD camcorder projects in studio 12 to mpeg2 DVD standard I use about 50-60%....if encode to a mpeg4 codec I get mid 70%.....if I encode to AVCHD I hit mid 90%....what is that telling us?

 

[soccerballtux]

Your harddrive should not be the bottleneck.

Your CPUS are only 70% I believe because the Core I7 has hyperthreading. So while the processor may see 8 cores, they're not 8 true cores-- the hyperthreading just makes sure each of the 4 cores is always working on something. That you're getting 70% (and not 60-65%) or 90%(!) is quite impressive. This is a bad explanation, someone could do much better.

In Vista right click your task-bar, open the task manager, click the "Performance" tab, click "resource monitor" down at the bottom and tell us what your disk activity is like when encoding to AVCHD and when encoding to the HDcamcorder stuff. Is it pegged to 50megabytes/second?

 

[Duvie]

Originally posted by: soccerballtux
Your harddrive should not be the bottleneck.

Your CPUS are only 70% I believe because the Core I7 has hyperthreading. So while the processor may see 8 cores, they're not 8 true cores-- the hyperthreading just makes sure each of the 4 cores is always working on something. That you're getting 70% (and not 60-65%) or 90%(!) is quite impressive. This is a bad explanation, someone could do much better.

In Vista right click your task-bar, open the task manager, click the "Performance" tab, click "resource monitor" down at the bottom and tell us what your disk activity is like when encoding to AVCHD and when encoding to the HDcamcorder stuff. Is it pegged to 50megabytes/second?

Do you know how to see that on WinXP? Does it have something like that?

 

[soccerballtux]

no

 

[TurtleCrusher]

Encoding barely requires a fast drive. My system at max quality encoding an AVI file had speeds of 5 1/2mb per second, rather then my drives average sustained speeds of 52mb's. This is with my CPU being used at 100% while encoding x264.