2x 2.8 Ghz Quad core Xeon vs intel core2 quad core

Started by mt_sabao, February 17, 2009, 04:53:59 am

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mt_sabao

Hi everybody,
I'm running the latest version of terragen (1.10.23.1) in MacOs (10.5.6) at work on a 2x 2.8Ghz Quad core (so, 8 cores, and 8 GB RAM) and at home in vista 64 on a single quad core (4GB RAM). And on mac os i'm getting the triple of the render! 6 minutes for a specific scene and at home, vista 64, single quad core, 2 minutes (I don't remember from the top of my head which speed i have at home, but i think it's 3Ghz)

Terragen says it detects 8 cores (on the mac) and 4 (on the pc at home), and under advance tab in render, i have minimum threads 4, max 16.

Is this normal, such a big difference?I know it's not linear, but still shouldn't i have smaller render times on the double of the cores?

Cheers

jo

Hi,

TG Mac doesn't scale very well past about 4 cores at the moment. This is most likely due to some issues in the OS, other applications which scale better on Windows or Linux have problems on OS X too. I suggest either setting max threads to 4 in each project, or going to the Startup preferences panel and overriding the number of cores detection setting, as described here.

I'll be looking into the performance issues once Apple have released new Mac Pro machines and I've been able to buy one :-).

Regards,

Jo

mt_sabao

wow, crazy. thanks for the fast reply, i changed the number of processores to 4 and now it's rendering much faster!
pity, 4 cores unused tough.

Tangled-Universe

Quote from: mt_sabao on February 17, 2009, 07:14:56 am
wow, crazy. thanks for the fast reply, i changed the number of processores to 4 and now it's rendering much faster!
pity, 4 cores unused tough.



You could always open Terragen twice and render the image cropped. One instance one half and the other instance the other half.
There could be differences in GI however, but these can often be resolved in postwork.

Martin

echrei

Quote from: jo on February 17, 2009, 06:48:55 am
I'll be looking into the performance issues once Apple have released new Mac Pro machines and I've been able to buy one :-).

Regards,

Jo


So, did you buy one? I'm interested in getting the Mac Pro and using all 16 render threads. I'll probably install Vista 64 to compare render times with. I need something to replace my single cpu G5.
15" MacBook Pro / 2.6GHz Penryn C2D / 4GB RAM / 500GB 7200RPM HDD / 8600M GT 512MB
Hackintosh / Dual X5680 @ 4.2GHz / 12GB RAM / 2TB HDD / GTX 480+260

jo

Hi echrei,

Quote from: echrei on March 05, 2009, 05:39:01 am
So, did you buy one? I'm interested in getting the Mac Pro and using all 16 render threads. I'll probably install Vista 64 to compare render times with. I need something to replace my single cpu G5.


With the price the new ones are I won't be able to get one for a little while. The 8 core ones are stupidly expensive, I almost wish I'd got one of the old ones instead now. Hopefully in the next few months though.

Regards,

Jo

old_blaggard

Keep your eye on the refurb store, Jo - you might be able to pick up a good deal there on one of the older ones.
http://www.terragen.org - A great Terragen resource with models, contests, galleries, and forums.

SilverCity

I plan on getting the 2.26 Octo Mac Pro (once I see some real world benchmarks). Will T2 be able to take advantage of all 8 cores, or is the 2.66 Quad Core MP a better choice? I'll be running OS X10.5 and eventually Snow Leopard.

jo

Hi,

Quote from: SilverCity on March 06, 2009, 06:44:50 pm
I plan on getting the 2.26 Octo Mac Pro (once I see some real world benchmarks). Will T2 be able to take advantage of all 8 cores, or is the 2.66 Quad Core MP a better choice?


It can't take full advantage of 8 cores now, but that doesn't mean it won't be able to in the future. At some point I will get an 8 core Mac Pro and start figuring out how to get it to scale better. Another thing to take into consideration is that Snow Leopard may improve the situation which currently leads to TG 2 Mac scaling poorly compared to TG2 Windows. We have to get TG2 scaling better past 4 cores, because that's the way CPUs are going.

The other consideration is that if you were doing animation you should be able to run two instances of TG2 ( not really officially supported at the moment mind you ) using 4 cores each on an 8 core machine. There's also the possibility of being able to split large single images across two instances as well.

I would say that long term the 8 core machines are a good idea ( if you can afford one! ).

Regards,

Jo

SilverCity

Thanks for that well thought out response, Jo. I'll go for the 8 core, then. Since I plan on using this computer for the next 3-4 years, the cost is well worth it, I figure.

old_blaggard

Keep in mind that you're actually getting 16 logical cores with your 8-core Mac Pro because of Intel's SMP implementation. I believe that FrankB managed to use that to great effect, basically cutting his render time in half. Again, not particularly useful if you're running TG2 on the Mac side right now, but we'll see what improvements Snow Leopard will bring.
http://www.terragen.org - A great Terragen resource with models, contests, galleries, and forums.

SilverCity

Quote from: old_blaggard on March 06, 2009, 08:38:28 pm
Keep in mind that you're actually getting 16 logical cores with your 8-core Mac Pro because of Intel's SMP implementation. I believe that FrankB managed to use that to great effect, basically cutting his render time in half. Again, not particularly useful if you're running TG2 on the Mac side right now, but we'll see what improvements Snow Leopard will bring.

Yes, this is why I think the new MP's are better than the previous model. A lot of people are turned off by the price and seeming lack of a speed bump over the 2008 8 core MP's. Many are instead looking at getting 2008 MP refurbs. But, I think in the long run, these Nehalem models will be a better deal.

old_blaggard

Eh, the benefits from hyper-threading are pretty application-specific, and Mac OS X won't do a great job of using them until Snow Leopard. That's partially why I'm waiting until June or so myself to see what I'm going to get.
http://www.terragen.org - A great Terragen resource with models, contests, galleries, and forums.

echrei

The benchmarks for the New Mac Pro are quite amazing.

The 3.2GHz Mac Pro got an average score of 8,853
The new 2.9GHz Mac Pro gets a score of 17,665    BAM!

http://browse.geekbench.ca/geekbench2/view/115605
15" MacBook Pro / 2.6GHz Penryn C2D / 4GB RAM / 500GB 7200RPM HDD / 8600M GT 512MB
Hackintosh / Dual X5680 @ 4.2GHz / 12GB RAM / 2TB HDD / GTX 480+260