Reality and LUX processor use.

Bendinggrass

I will soon be getting a new computer, and resources to work with Reality are high on my list.
I have been thinking about dual processors on a single motherboard, as the CPU is more important for Reality/LUX.
I know Intel i7 processor is effective, but I have also been looking at the Intel Xenon CPUs, and have yet to finally decide on that.
I know that if one is looking at a render farm it is the number of CPUs that matters most, and not so much the clock speed of the CPU. So in a similar way, would a slower 8 core Xenon 2.2 Ghz be more effective than, for example, a 6 or 4 core i7 ?

Also, am I correct in thinking that some Nivedia cards are now using OpenCL and so can be used with Reality/LUX ?

Thanks.
R

mjc1016

Bendinggrass said:

I will soon be getting a new computer, and resources to work with Reality are high on my list.
I have been thinking about dual processors on a single motherboard, as the CPU is more important for Reality/LUX.
I know Intel i7 processor is effective, but I have also been looking at the Intel Xenon CPUs, and have yet to finally decide on that.
I know that if one is looking at a render farm it is the number of CPUs that matters most, and not so much the clock speed of the CPU. So in a similar way, would a slower 8 core Xenon 2.2 Ghz be more effective than, for example, a 6 or 4 core i7 ?

Also, am I correct in thinking that some Nivedia cards are now using OpenCL and so can be used with Reality/LUX ?

Thanks.
R

A significantly faster 6 core will outperform an 8...but we are talking more than 500 MHz differences...in other words a 3.0 GHz 6 will beat a 2.5 GHz 8 or lower...both will beat a 4, unless the 4 is extremely OC'd or something. But that's on the speed end of things...'work' done...especially for something like rendering, more real cores are better, regardless of the speed (to a point). If you have 8 real cores churning away at a render, more is actually getting done at a time. (virtual cores still use some sort of 'switching' so with things that take a long time to do...like a render...those brief fractions of a second will add up...so a somewhat slower, but more 'real' cored CPU would be 'faster'...most benchmarks are done on things that take seconds or minutes to accomplish...not hours).

What it really boils down to is price...there isn't all that much difference as to be that noticeable at the 6 vs 8 core in the mid 2 to 3 GHz range...but with a dual CPU board, where you can drop in another 8 core processor at some point, then you are talking REAL differences.

Personally, I'm leaning toward a dual 12 core Opteron setup...

As to video cards...yes, Nvidia does OpenCL and has for awhile now...I got a 'cheap' GT 430 that works well with Lux (yeah it's not a powerhouse, but I can do hybrid or GPU rendering with it (only 96 cores for that...but that's 96 more OpenCL/CUDA cores than my last card had)). The key thing, though...get the card with the most memory...a 2 or more GB card is very desirable.

Bendinggrass

Hi mjc1016.

Thanks for your help on this.
My desire is to simply get renders done very fast, and to have good options available to use as needed.
It appears, from what you have told me, that the more real cores available, the better it is for rendering quickly, with conditions on that.
The Xenon cpus have prices that are all over the place, and up to 8 cores. Could you or someone here give me an idea about the Xenon cpus capability? I know they are often used in servers. And they are often thousands of dollars more than the best i7 so does that mean that the best Xenon can do "more work" than the best i7?

Interesting about the Nivedia cards now,
I want to use it to give Reality/LUX a boost (which requires OpenCL) but I also want it so I have the option of using Octane at some time in the future.
Could you and the other good folks here give me your thoughts about these considerations?

Thanks so much.
R

mjc1016

Any of the higher end Nvidia gaming cards (the GTX cards) do both OpenCL and CUDA...so a 680 with 2 GB or more of RAM would be a great card, if you don't want to get a Quadro.

Something like this...http://www.newegg.com/Product/Product.aspx?Item=N82E16814130768

but you could even go as low as this...

http://www.newegg.com/Product/Product.aspx?Item=N82E16814130586 (only 16 cores...not much help there...but it is still 'usable' for GPU rendering..)

As to the CPU...if you really want the option to go with dual CPUs then you are stuck with a 'server' type...but at the middle of the road a high end i7 and mid Xeon will perform about the same, with the i7 probably coming out much, much cheaper. (there are other things involved, like cache sizes that are of some concern, but for the most part aren't that important to consider)...

I'd really love to set up a dual configuration with these...
http://www.newegg.com/Product/Product.aspx?Item=N82E16819113040

Bendinggrass

The Opteron processor you showed me is interesting, at 16 cores.
Is that actually 16 cores, or 8 cores with dual threading?

You mentioned, I think, the option of getting a dual processor motherboard,
and using one processor until a second cpu can be bought..... afforded..... :)
This is possible? If so it is a great option.
Is it necessary to use identical cpus or can the two chosen be of different core count, clock speed... ?

Thanks, this is a great help, and fascinating also.
I was looking at a company which builds dual core computers/workstations, and it appears to almost be about
the same cost to buy one of these as to upgrade my present computer with new parts, etc.

R

mjc1016

Most dual boards do allow for using only 1 socket...and yes they need to be matched.

Opterons are all 'real' cores...most server processors are.

A decent builder can get there for not much, if any more, than upgrading yourself...but bear in mind, that going the builder route can be hit or miss, although in the workstation market it's more hit than miss...because if you get a rep for poor/shoddy work, you aren't in business very long when dealing with buyers that are demanding 'high end'.

Bendinggrass

Interesting site for built dual processor machine here:

http://www.titanuscomputers.com/

And for the Opteron:

http://www.titanuscomputers.com/A350-AMD-Workstation-Interlagos-32-cores-p/a350.htm

Yes, it appears to be competitive with the cost of upgrading to this quality, without all the headachs involved.