Revit and Intel Core 2 Duo Processors

[saeborne]

Does Revit benefit from processors with multiple cores?

Do you notice a benefit when moving from a single Core 2 Duo, to a computer with dual Core 2 Duo processors, or a Quad Core processor, or even the new Mac Pro 8 Core processor?

Many thanks,

[twiceroadsfool]

Youll notice a difference because the second processor is free for the other stuff, to an extent.

But Revit wont actually use both processors. Accurender INSIDE Revit will, however.

[saeborne]

Youll notice a difference because the second processor is free for the other stuff, to an extent.

But Revit wont actually use both processors. Accurender INSIDE Revit will, however.

Thanks for the info. That's very interesting.

For a moment, let's assume a typical CAD user is multi-tasking the following applications:

Revit
Outlook
Word
Excel
Firefox
iTunes

Fairly light weight stuff.

Is there an advantage to buying a single Core 2 duo processor vs. a dual Core 2 duo processor?

[Calvn_Swing]

Yes and No. (The answer is never simple.)

Revit is not Multi-threaded. So, you gain nothing going from a single core, to a dual core, to a quad core if all you have running is Revit.

Of course, most computers have 20+ processes running at once, so you do gain some benefit from a dual core processor as Revit can actually use ALL of one processor while the other "junk" uses anywhere between 10% to 15% of the other one.

This advantage increases as you scale the number and demand of the "additional" applications. So, if you like to have Revit, Photoshop, and ADT running all at once, you might actually benefit from the jump from dual to quad core. (Whether it is 2 dual core, or one quad core is irrelevant aside from the price difference)

Now, that being said, the accurender engine in Revit may be multi-threaded, in which case you can utilize as many cores as you can throw at it. However, I know very few people who use Revit for rendering. Still, if you do any rendering (Max, Viz, FormZ, etc...) then you can use all the cores in those applications as well.

The last piece of the puzzle is that Revit will EVENTUALLY be multi-threaded. So, one day, you will be able to use more than one core. It all depends on what kind of divisions are efficient for the software. In general, 3D modeling is a fairly sequential task, which doesn't thread well. You might think of it like worksets or linked files. It makes sense to have two separate buildings in linked files. It might makes sense to have the interior and exterior of a building on their own worksets. But it sure doesn't make sense to put windows on one, doors in another, walls in another, etc...

At some point one thread depends on the effects of another thread, and then you're in big trouble. So, will Revit ever be able to saturate 8 cores during normal use of the software? Maybe, maybe not - I'd guess not. But, 2 or 3 threads is not unrealistic at all in the next few years. So, maybe a Quad core is the right choice now (for Photoshop and your music stream) and for the future when Revit becomes SMP aware. (Multi-threaded).

Our firm just received our new workstations (3 year lease). We got Dell workstations with a dual socket motherboard. We currently have one Quad Core 2.66 Ghz Xeon processor in it, with the intent to put in a second one in a year and a half. We have 4 Gigs of Ram currently, with the intent to upgrade to 8 Gigs in a year and a half. Our bet is that we'll use whatever power we have, even if Revit isn't using it all. Personally, I like running Revit full speed on my computer while having a Viz Rendering on the other three processors in the "background." Our renderings come out in less than 1/4 the time it took just a week ago, and I can keep working in Revit at the same time. Pretty darn nifty...

Edit: iTunes is not "lightweight" just so you know...

[twiceroadsfool]

I second what Calvn said. ITunes is BRUTAL, compared to other music players out there. I personally use winamp Classic, becuase its pretty lightweight, and im sure there are some even better than that. We have one Revit user here who insists on running Itunes, and her computer has troubles with big models, when the computer runs out of memory.

Our IT department has put it on a *list* that is supposed to come out, of things NOT to be on our systems, lol.

That said, i have 2 dual Core systems for Revit, and i love them. Even if (today) i cant benefit from it in straight capabilities, i benefit from it in other ways. Ill open two instances of Revit, and work in one while the other is saving to central. Or ill do that for working in linked files.

[saeborne]

Thanks for the responses.

Is there any idea as to when Revit will become SMP aware? Revit 2008?

[Calvn_Swing]

No, the Autodesk developers have been very close-lipped about this one. Like I said, modeling is a very sequential task. So, I imagine they're wracking their brains over there on how to make it SMP aware.

That being said, I'd expect it in the next release. By the time they get around to that, a majority of firms will have dual core processors at the least. So, they'd be foolish not to. Also, the rumor mill is that ArchiCAD will be SMP aware on its next release, so Autodesk will probably try to match that even if they haven't got a great implementation of it. Marketing sometimes drives innovation, though usually it is the other way around...

Then again, I counted on it being out in this release. So, obviously I'm just shooting in the dark...

Edit: the "Rumor Mill" in this case is a friend who isn't the most reliable source of information. So take that with a BIG grain of salt. I personally don't know jack about ArchiCAD nor do I hang out on their forums, so he's the only resource I have...

[jeff.95551]

With 2 processors many processes will still operate on both - apparently Windows doesn't actively manage that process. If you have a multiple processor machine, you can set the 'affinity' (official term) of processes to a particular processor, so that most processes will run on processor 0, and Revit can be assigned to processor 1. The machine I'm sitting on isn't dual core, so that option isn't even present, but I recall it is accessed through the windows 'system' control. I don't think you have total control over that, but it gives you some control. Without that, often you will notice that even with two or more processors, almost all the work is being done with one processor and the other is completely idle.

I'm sure some of you have more specific knowledge of this.

Jeff

[ron.sanpedro]

No, the Autodesk developers have been very close-lipped about this one. Like I said, modeling is a very sequential task. So, I imagine they're wracking their brains over there on how to make it SMP aware.

I think we would all see MUCH more performance increase from a 64 bit NON SMP Revit and 8G or even 16G of RAM. Of course until the printer manufacturers get off their duffs and write drivers, we are still dead in the water. But given the choice, I would rather see 64 bit sooner, and SMP later.

Just my $0.02 anyway.

Gordon

[Calvn_Swing]

You're right about setting affinity.

The simplest way to access this is to go to the Task Manager, find the process of the particular program you want to affect, and then right click on it and set its affinity.

Windows XP/2000/NT does a decent job of managing processes, and Vista does a much better job. The problem is that processes that have minimal impact are rarely load balanced against large applications like Revit. However, when one process is requesting all of the resources on a particular processor it will move other processes around accordingly, or move the resource hog application appropriately. So, it isn't completely dumb. It just isn't as efficient as it could be. If you're running Vista. I wouldn't worry about it. If you're running anything else, and you want to go crazy - Viz on 2 processors, Revit on one, and one as a spare/overhead then I'd use the affinity settings. I use the task manager because it is a case by case basis. Next time you run the application the settings are reset. I believe there is a way to permanently assign affinity for a program, but I've never had a use for it. My patterns are just too varied, and the automatic settings are good enough most of the time.