This thread is getting more interesting by the minute and it is not even about Houdini! wink Keep on talking twod! I wonder if J.C. well ever make the right choice now, he must be utterly confused P

JColdrick
I'm not sure I trust the estimated vs real-world results of the quad-core cpus. One thing I do know, especially when you're talking rendering, one core doth not equal one cpu - there's some serious bottlenecks in there.

I've been trying to find comparisons that highlight that. The only one I found so far is the single vs. multiple core Cinebench benchmark at c|net http://reviews.cnet.com/4532-10921_7-0.html?authorId=1011703 [reviews.cnet.com]

From what I gather, a dual quad-core is about 4.8 real cpu's worth of processing power (61% efficiency), and a dual dual-core is about 3.2 real cpu's worth (81% efficiency). However, a “new” core at 3Ghz I'm told is about as fast as an old single-core 3.6Ghz (roughly). Does anyone have any more data on this?

– Antoine

From what I gather, a dual quad-core is about 4.8 real cpu's worth of processing power (61% efficiency), and a dual dual-core is about 3.2 real cpu's worth (81% efficiency).

That sounds about right for threading, though I'm a little surprised the 8-CPU test is as low as it is - perhaps the image rendered isn't that large. There's always some overhead with threading, as well as blocking for resources (like computing a tex map or a mesh). Lock contention increases as the number of threads increase, so this tends to eat into the threads' time doing actual work. You can almost think of it like traffic - the more threads (cars) you have, the more people (work) you move, up to a point – and then everything begins to plateau (the cars move slower, so having more doesn't help).

A good test would be to set up a series of frames (a multiple of 4) to render using a Makefile. Then, do

time make -j1
time make -j2
time make -j4

This way, you're running multiple render processes on the system, so presumably there will not be any contention (except for system resources, like hard drive usage and memory). Of course, you need a lot of memory on that system to support 4 non-trivial frame renders at once.

Another good way to saturate a quad-proc might be to do 2 frames at once, threading each one by 2. You get the memory usage of 2 frames (roughly), but the performance of two threads on each (usually 1.8x; 2 threads normally has the highest efficiency of any number other than 1). I would suspect this would beat doing a single frame with 4 threads (but again, you could test this with the Makefile test by adding a THREADS=N option).

Late, but still pertinent!!

Barcelona came and well…

JColdrick, did you get your “new” computer? Have you been happy?

and now that it is more than 6 months old would you like to pass it along? :wink:
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continuing from the thread: someone mentioned an upgrade is usually 2x faster. is this the norm? how about for a home pc?

trying to get the most bang for the buck, money is an issue. that said, i'm thinking that the 2nd upgrade (or addition / replacement) will happen much sooner as new technology will most likely make anything i get now very much obsolete.

so, consumer level single socket pc, 2-4gb ram, with possibility of going “starving artist” hd res: dual, tri, quad?

side q: how long should an average frame take to render on a home pc? reworded: how long can the average houdini artist wait for one frame to render (at home)?

E7200 vs. Phenom X3 8450 ( http://www.legionhardware.com/document.php?id=751&p=0 [legionhardware.com] )

but am also considering (for the extra cost savings while i sit scratching me head… aka “thinking”): the 45W AMD Athlon X2 4850e 2.5GHz

it's already known this would be rather slow compared to the others. does the 400mHz divisible thing apply here as well? would underclocking it speed it up? yes, i realize what i just said… but to 2.4gHz… lose 0.1 gHz, but potentially gain the lost memory speed.

on the E7200, ppl have said it has limited cache. but cache is transistors and those guys give off heat… heat costs money, but so does time. thoughts on cache?

or would a quad be more applicable now?

lastly, would probably get no less than 2gb of ram with (eventual) max being 4gb. how does this correlate when scaling cores?

thanks in adv.

Yes, it's been a while. Essentially multiple cores are considered a standard now, and if you're going to use the system to do any rendering, then as many as possible. Even some sim stuff, like particle fluids I believe, will thread. Our new machines, as we get them, have 8 cores. You don't *have* to get dual quads, for home a single quad is fine, but I'd say it's a no-brainer now. Unless cost is an issue, get a quad over a dual.

Cheers,

J.C.

I'd also suggest trying to get a motherboard that allows you to add a second quad processor later should you desire it.

Well, if you're looking for a starving artist rig, then I'd look at something like:

Core2 Q6600 ($250)
3GB (32b OS) or 4GB (64b OS) DDR2-800 RAM (~$100)
Basic P35 motherboard with Gb LAN+audio ($100)
Nvidia 9600GT ($150)
Samsung Spinpoint F1 750GB ($150)
DVD writer ($50)
24“ LCD 1920x1080 res ($450)
basic key+ 3B mouse ($60)

Total cost: ~$1300 (CDN)

You could drop the monitor down to a 20” and save another $200, but as that's the thing you're staring at all day, I tend to urge people not to skimp on it. You'll eventually want to replace it with a pro model for better color fidelity (in the $800-1200 range).

Prebuilt systems can hide some of the cost for you (like the OS if you're going Windows) but you'll likely have to add extras to them (like a larger, faster HD). They also rarely come equipped with a 64b OS, which I pretty much consider mandatory for any new system these days.

Hope that helps.

Don't get vista. Beg, borrow or steal(you didn't hear that here ) XP since I wouldn't run Vista on a rig like that. Better yet, get Linux.

Cheers,

J.C.

somehow i wasn't informed about page 2…

thanks for the revisited discussion and the advice.

the Q6600 has been around for a year!!! this bothers me, but being financially handicapped doesn't help either. the weird thing w/ the Intel quads is the newer procs are a little faster, but have less cache… until you get up to the high end consumer stuff. all of this may be moot when Nehalem finally debuts… which offers those of us in my situation w/ something else to drool over and the hope it'll drive the older tech lower.

i've dreamed of an open system where being able to insert a card w/ another proc or 2 would be a snap… think mini rack beside your desk… grows with you. i suppose this is a Boxx or something. again, affordability plays a role in this.

more train of thought meandering: Rackable systems has received praise for being more energy efficient w/ a setup that takes 2 half depth motherboards and splits one very energy efficient psu amongst them.

when will laptops go quad??? has anybody ever seen someone bring their home pc into a library?

lastly, has anybody graphed how much wasted cycles go to those learning software? i'm sure this graph is growing exponentially over time as computers get faster and software gets bigger. :wink:

42

Edit: according to wikipedia… http://en.wikipedia.org/wiki/List_of_future_Intel_Core_2_microprocessors [en.wikipedia.org] intel will launch a mobile quad in Q4 2008.

game on!