Dual core can render 4 buckets in Vray?

[sin81]

Im now using a intel dual core computer and I dont know if it can render 4 buckets in Vray. Now I see it can render 2 buckets at the same time, similar to HT CPU. Can anyone help me ? Give me the answers for this situation?

And how about WINXP 64bit? Can it help?

[DavidR]

Yes, it can render 4 buckets in Vray. Our old single-core Xeons with HT on render 4 buckets, though 2 are slower, and our Opteron 275s render 4 full-speed buckets, and are twice as fast as the Xeons. Turn on HT in your BIOS to render 4 buckets with 1 dual-core Intel, otherwise it'll only do 2. HT will speed rendering by ~20%.

[AJLynn]

I think only Extreme Edition dualcores would give you 4 buckets - those have Hyperthreading, so 2 CPUs pretend that they're 4. It gets you maybe a 10-15% advantage. But dual-core is an inherently faster tech than HT, so if your dual-core is not an EE, it's still faster than your HT chip.

 

But not as fast as my Core Duo

[CVC]

... yes . if your DC is not Extreme Edition ( with HT) , ucan fake it also by comand to get 4 bucket or more , try this command: renderers.current.system_numThreads=4

[gfa2]

Does this mean that a system with dual dual-core opterons would give you 8 buckets with hyperthreading? Man how cool would that be. If that works I need to get a new computer.

[Ray]

... renderers.current.system_numThreads=4

Where would you enter this?

[AJLynn]

A couple notes-

 

-AMD chips do not have Hyperthreading. They don't need it. HT is just an Intel hack that only works because the P4 architecture is so inefficient - it has many more steps in its pipeline than P3, Pentium M and AMD chips (30-something compared to 12 or so), which allows it to squeeze in more operations by starting a new one while there is a gap in the pipeline. This is not a revolutionary thing, it's just compensating for an inefficiency that Intel built in in their rush to make clock rates higher - because it's better for marketing when they can sell a 3GHz chip instead of a 2GHz chip, even if the 3GHz chip isn't actually faster.

 

-This doesn't mean the HT chip is faster than the others, or even very much faster than a non-HT version of the same chip, and it doesn't mean (despite the hype campaign they ran a few years ago) that you have the full effect of 2 CPUs. The effect in Vray is that you get an extra bucket, but each bucket is running slower than it would on a non-HT CPU.

 

The only real advantage of HT is when you're running two single-threaded programs at the same time, program A is in the background doing a lot of CPU work and you're actively using program B. The HT chip will do a better job of running B - HT will handle it more efficiently than Windows multithreading would on a non-HT system because HT operates at a hardware level, with fewer steps between it and the CPU core.

 

-Running more buckets than you have CPUs (or cores, or virtual CPUs in the case of HT chips) does not make Vray faster. The single bucket is already able to max out the CPU. The extra bucket really just wastes some memory.

[Ray]

With HT and without HT:

[AJLynn]

Wait a minute... you got HT to halve your render time? I never saw it clocked at better than 15% improvement. What exactly was the difference - HT on and off in the BIOS or just number of threads in Vray? How many threads on which CPUs each time? (That's a dual-core EE with HT, right?)

 

Can you tell me where to get the test scene?

[AJLynn]

I think I figured that one out. Found the scene and rendered it, 18:02 on an AMD 3000 with 1 gig - with Vray 1.47.03 but there shouldn't be much difference. The Intel chip that rendered those two images was a Pentium EE dual-core HT at 3GHz with 2 gigs. The slower one is consistent with using one core, the faster could be two cores with or without HT. It's the second CPU that's providing the speed increase, not the HT.

[radioVOY]

Hey Andrew can you share that scene????

[CVC]

-Running more buckets than you have CPUs (or cores, or virtual CPUs in the case of HT chips) does not make Vray faster. The single bucket is already able to max out the CPU. The extra bucket really just wastes some memory.

 

you are right , more bucket need more RAM but it's just for funny may be good

[AJLynn]

Hey Andrew can you share that scene????

 

Sure, I just Googled the scene name in the watermark and got this:

http://www.treddi.com/forum/index.php?showtopic=5303&st=10&p=57571entry57571

 

Link is in the second post.

 

BTW, I realized my old copy of Viz was still valid, installed that on the Bootcamped Macbook Pro 17, and it rendered the scene in 5:24.

[CHE]

Hi Andrew,

I got my Mac Book Pro 17 yesterday...what a beauty!!!

Right now I am running some tests in Modo (OSX). I was wondering if there is a difference in speed if I enable hyper threatening in the BIOS as opposed to do it in Modo (4 threads). If enabling it in the BIOS is the way to go, could you explain the steps I have to go thru?

Thanks,

Ernesto

[AJLynn]

The Core Duo doesn't have hyperthreading - that's only a P4/Xeon thing, and will probably be phased out as those lines are obsoleted by multicore chips with more efficient architectures. (Don't worry, your Core Duo is much faster than the P4HT.) Using 4 threads in Modo instead of 2 won't give you any bonus.

 

Have you started working in any of the included Apple software? Garage Band is incredibly cool. I've been mucking around with that and the C4D 9.6 demo with Mograph, I think I'm going to need to get a low-end midi keyboard and start using it for architectural design.

[mibs_studio]

After all i read all these thread, is it possible that my double dual core ( opteron) can have 8 buckets in rendering? Right now my rendering only have 4 buckets. I`m using Asus K8N-DL that can support 2 Opteron dual core CPU ( I assume as Quad-core ) 2 GB of ram + Quadro fx540 (entry level)...........

[CVC]

After all i read all these thread, is it possible that my double dual core ( opteron) can have 8 buckets in rendering? Right now my rendering only have 4 buckets. I`m using Asus K8N-DL that can support 2 Opteron dual core CPU ( I assume as Quad-core ) 2 GB of ram + Quadro fx540 (entry level)...........

your rig can't have 8 buckets

[DavidR]

After all i read all these thread, is it possible that my double dual core ( opteron) can have 8 buckets in rendering? Right now my rendering only have 4 buckets. I`m using Asus K8N-DL that can support 2 Opteron dual core CPU ( I assume as Quad-core ) 2 GB of ram + Quadro fx540 (entry level)...........

 

If you have 2 Opteron CPUs which are each dual core, then you should have 4 buckets rendering in Vray.

[mibs_studio]

If you have 2 Opteron CPUs which are each dual core, then you should have 4 buckets rendering in Vray.

 

Yes I`ve 2 Opteron CPU and each one is dual-core, so my workstation working as the way it is. Thanks....

[Noiré]

Does this mean that a system with dual dual-core opterons would give you 8 buckets with hyperthreading? Man how cool would that be. If that works I need to get a new computer.

I run a dual dual-core Xeon system with HT on(and 4GB RAM), and this not only gives you 8 buckets, but renders siginificantly faster than with HT turned off. Ufortunately I don't have any numbers to confirm this, but even though HT in theory should not increase performance that much, it seems to do so when rendering with vray, provided you have enough RAM of course.

[AJLynn]

Could you do some comparisons? I'd like to see what HT does to Xeons.

 

Opterons still don't have Hyperthreading (Some people get confused because Opterons have Hypertransport, which is also abbreviated HT, but that's completely different and has nothing at all to do with what we're talking about, so please, nobody ask if they can use Hypertransport to double their buckets.)

[mibs_studio]

Nothing to do with intel HT what so ever, another comparison between AMD 64 3200++ with Double Opteron Dual Core ( Quad-core)

 

[Noiré]

Dual Dual-core Xeon with hyprethreading turned off:

Dual Dual-core Xeon with hyperthreading turned on:

[AJLynn]

That one I can believe.

[Noiré]

HT increases performance with Vray by 28,5%. No more, no less. I'll keep HT on, that's for sure;)