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Dual Xeon slower than dual core


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I know there have been many discussions on this, but I refuse to believe what I am seeing..

 

I have a 6 month old Dell Workstation, with Dual Xeon 3.2's.. rendering with 8 buckets.. pretty fast eh..?

 

Well not really. We also have a 3 month old Dell Dimension.. (I think) with an Intel Core 2, 6600 @ 2.4.. renders 2 buckets.

 

Now I have a scene that takes 77 secs to render on the super duper Xeon ...

 

And 56 secs on the Core 2..:confused:

 

I know that the way the core 2 works within the same core on the chip makes it very efficient.. but 2 buckets against 8.. and pretty up to date Xeons..??

 

Does this sound right..? I just cant believe that that should work like that..? Could there be a problem within my workstation..?

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The fastest Core-based Xeons are 3.0GHz, so a 3.2 is a Netburst core. If you have 8 buckets, these are, what, dual core, dual CPU with Hyperthreading? Or are you just forcing the 8 buckets where there are 2 or 4 logical CPUs? Anyway, the Core2 chip's GHz are worth twice as much as a Netburst chip's GHz, so the dual 2.4 is a dual 4.8, in translation. Add in any other factors - e.g., the 8 bucket system will need a ton of RAM and anybody who's Cinebenched an 8-core machine can tell you that you lose efficiency with that many render threads, so it might actually be slower for you to render with Hyperthreading than without it.

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Just checked out on Dell website.. its older than I thought, but still less than a year. Shipped 27th July last year.

 

I have queried the processor on the dual Xeon.. the attached is the exact data from that query.

 

Does this make things clearer..?

 

This data is the the actual model from the dual Xeon, not the Dual CORE chip. The data here is for the chip that renders with 8 buckets... the slower of the two..!!!

 

As far as I know, I am not forcing any extra buckets etc.. this is virtually straight "out of the box" machine, with the addition of Win XP Prof SP2...

 

Cheers

 

Andy

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So what you have is 2 CPUs, 2 cores total, which are hyperthreaded Netburst cores at 3.2GHz. Total of 4 logical CPUs, for an optimal configuration of 4 buckets, not 8.

 

Versus a Core2 Duo, 2 cores total, 2.4GHz of Core microarchitecture, 2 buckets optimal.

 

Of course the Core2 beats the crap out of the Xeon. It's a much faster system.

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Do you have a manual setting for renderers.current.system_numThreads

 

e.g., renderers.current.system_numThreads=8 would force 8 buckets, renderers.current.system_numThreads=4 would force 4, and no setting would make it guess.

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sounds like you and I have the same machine...and same "problem" - a Dell Precision 690 with Dual Xeons (but I only have 3.0ghz chips). Recently bought Dimension 9200s with E6600's and sho nuff, my almost $3000 badarse is slightly slower than the $1200 Core2Duo. Annoyed me as well....but since it's not TOO far off from the others, I don't mind as much.

 

and yes, we DO get 8 buckets straight outta tha box.

 

ME

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Interesting...

 

I ran a little test on that settings Andrew.. cheers for that.

 

Changed it between 0 - 32.. this is what I got:

 

Threads 8 = 1 min 21 secs

Threads 4 = 1 min 28 secs

Threads 0 = 1 min 29 secs (threads null so system decides)

Threads 16 = 1 min 19 secs

Threads 32 = 1 min 19 secs

 

I have left it at 8 threads.. seems going too high could be asking for trouble..

 

So.. in summary.. it seems Andrews description of the Core 2Duo kicking the dual xeons butt is spot on..:(

 

Shame, as the dual xeon cost about the same as 3 of the cheap Core 2's....!

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