View Full Version : Hardware question: Bi-Xeon or i7

01-13-2012, 05:07 PM
Hi there! I'm about to mount a new computer (around 2500/3200$) and have a question about CPU. As I didn't have a renderfarm and as I'm mainly doing still picture for arch viz, I need something to do many rendering test and able to render high resolution pictures as fast as possible.

So I was thinking about bi-xeon: http://www.ldlc.com/fiche/PB00111291.html (sorry it's in French, but it's a 6 cores, multithreaded, 2.4 Ghz)

But now I see that some i7 processors (i7-3960X for instance) seams to be really fast too.

So I would like to know if some of you have been able to compare this two kind of setup with LW rendering?

Thank you! :)

01-13-2012, 06:03 PM
Dual Xeons are only worth it if you go for a pair of top end X5690 CPUs in a workstation. Add up the cost of parts for the whole computer including OS. Then divide this by the number of GHz. Techreport http://techreport.com/articles.x/21987/13 has the 3960 & 990 using Cinebench which will be relatively similar to LW (for a pair of X5690 speed wise it's basically two 990X CPUs). You can also overclock the 3960 easily. The Xeons you can only overclock if you buy an expensive MB. People make the mistake of looking at the price of the CPU alone.

Basically for rendering you are trying to buy the maximum number of GHz per dollar. Dual Xeons are good for baking large radiosity cache files or if you have large single frame renders. But there are work arounds.

Especially with Radiosity a GHz on a current CPU is a lot quicker than a GHz on CPU a couple of generations old like x54xx or worse x53xx.

The following is an example a few months old but gives you an idea (it's an update to my dual W5580 box which has 25.6GHz of processing which I bought in July 2009):

2 x X5690 $3650
Supermicro X8DAL-i $486
Supermicro 865w power supply $373
Chenbro SR11269 $218
24GB Ram Corsair1333 ECC REG 4GB x 6 $775
2 x Noctua heatsinks $160
Intel X25-M SSD 120Gb $211
2 x 1TB HD $150
Gigabyte GTX560 $269
CD/DVD $38
Win7 professional $162

Total price au$6492.00 (41.52GHz) $156.35 per GHz

01-14-2012, 04:21 AM
You can check this thread:
where some people made speed tests with two sample scenes.

Result on my older dual Xeons:

Dual Xeon E5520 2.27 GHz / 12 GB Ram / Win7 Ult. 64 Bit / LW 10.1 64

_______ HT off (8 core) | HT on (16 core)
Smoke: ________3m 21.0s | 2m 34.0s
Robot: ___________32.9s |____26.4s

Which was only a few seconds faster than with ONE new Core i7 sandy bridge desktop CPU (IIntel Core i7-2600 / quad core).

Now the even faster:
- Core i7-3960X (6 core)
- Core i7-3930K (6 core)
- Core i7-3820 (4 core)
desktop CPUs are available.

So you get a lot of speed with ONE desktop CPU.

BUT, the new Xeons (Xeon E5-xxxx line) that are based on the same architecture than the Core i7 CPUs are anounced for the first quarter of 2012. There will be 8 to 4 core models. So you can expect to get the speed of the Core I7 desktop CPUs, but you can put two of the Xeons on a workstation or server mainboard.

check this before you decide:

01-14-2012, 06:06 AM
Compare this list (dual-cpu)
with this:
and you will see how much of speed you can get from multiple cpu solution, if money is not problem..

01-16-2012, 11:13 PM
This scene is 103 sec on my Pair of W5580 CPUs.

They have the 3960X at 3.3 GHz 63 seconds & at 4.75 GHz 52 seconds


01-23-2012, 02:48 AM
JonW, thank you very much for all this details!

Xeon X5690 are sadly too expensive for me. Indeed the i7 3960X seams
to be interesting, but I didn't know a few thing about OC yet. That
say, I've seen the the Xeon W3680, which is not too expensive,
get 6 cores at 3.33Ghz and is multithreaded. So on the paper
and for a "low" price, it seams a really good deal! What do you
think about this one? What is the reason to have such capacity
and still be so cheap? (Well it's always almost 600 by
CPU) ....Anyway as I'm still on my old Q6600 2.4Ghz, first render with
each solutions will be a great moment of glory :D

madno, thank you for the link, very interesting indeed!

Sensei, thank you for the link. True that high end mutli cpu seams
to be amazing but, wow, what a price! That say, Athlon seams to have
really good result, wasn't expecting this.

01-23-2012, 03:23 AM
Remember that the costs of running Xeons doesn't stop with the processor, there's also the higher costs of the motherboards and potentially only being able to run ECC memory which is also more expensive.

I've got a dual Xeon BOXX which I still use as a secondary workstation and render node but I use an i7 because it's faster, cheaper and the running costs are lower due to fewer components. Personally, I'd rather replace an i7 based PC every year or two than have a Xeon based workstation which I can only afford to replace every 3-4 years.

01-23-2012, 03:43 AM
Have a look at this thread, we're talking a bit about large scenes, post 11 there is a link to a benchmark http://forums.newtek.com/showthread.php?t=125147 using 3960 & 3930 at Bit-tech.

My 920 & 940 clocked at the same speed as my W5580 will do a render in half the time as there is obviously 1 CPU instead of 2. All these CPUs are from the same generation.

So for example a 6 core CPU & if you overclock it, it will do a render in 2/3 the time plus the difference the CPU is faster than the comparison CPU. It's just a straight forward calculation.

It's only worth buying a Xeon for a workstation if you get 2 of them & buy the top end. For a single CPU & on a budget of some degree I would look at the new 3930K. it does the 3dspeed scene in 71 second as against my current generation W5580 (x 2 CPUs) 63 seconds. That's impressive. If funds are tight upgrade other things later, you could even move your graphics card to the new box for example.

3dspeed, no one has added CPUs here for a while but is gives you history that's not too old. http://3dspeedmachine.com/benchmarks/render-times/lightwave/

Q6600 are around 4 minutes, also LW9.6 only does 16 threads, so 24 thread boxes are under performing.

01-23-2012, 06:36 AM
Thank you for this words of wisdom! I was thinking that the W3680 could be mounted on a 2 cpu configuration. And with my budget, if I go for a Xeon serie 5000, it would be 2 x5650 top (around 2000) where a single 3930K (around 500) would have similar performance with OC, you're right :)

So I guess my next step now is to learn a bit more about OC, isn't it a bit dangerous to use this method? Could I choose the CPU frequency directly in windows or should I go in BIOS?

I hope it's not to much question and that there is other forum for that, but opinions of Overcloked Lightwaver is always better to have :)

01-23-2012, 01:29 PM
My i7 boxes came with OC software but I stuck with BIOS & I just did a search on the internet. I had no idea what I was doing. So I only did a mild OC, also the box was stuffed full of ram which apparently reduces the maximum OC.

You will be so blown away will speed of a new CPU. Just leave the overclocking until you have done some research & get tired with the performance of the box, I wouldn't get stressed over it.

I'm still impressed with my main box (& I can't OC it) & unless I'm rendering a very large image with lots of transparency & reflections I can survive quite nicely.

Get Screamernet going & use your old box, especially if you are rendering frames.