single fast or two slow CPU

[radioVOY]

hi there!!

 

another computer question:

 

lets supose that we have a dual xeon64bit 3.0ghz 800fsb 1 mb L2 cache and a single P4 64bit 3.2ghz 800fsb 2mb L2 cache (two for renderfarm), wich one will be faster???

 

as far i know a dual procesor machine running at 3.0ghz is not faster than a single 3.0ghz machine, but is stronger and support a lot of tasks at the same time, so if the machine is intended for renderfarm, that machine just work on two tasks (windows and max), then maybe a single but fast and strong procesor will be a cheaper solution for renderfarm.

 

may be im wrong so if anyone can help me to understand this a really apreciate, i got a us$2500dlls budget to start a renderfarm thats why i need to do a good but not very expensive election.

 

thanks in advance for the replies.

[STRAT]

hmmm. a dual processor running at 3.0 ghz is nearly the equavelant of a 6 ghz machine. (2 X 3.0 ghz)

 

my dual 2.8's are twice as fast as my single 2.8. thats the whole point of a dual.

[ihabkal]

I noticed in Vray your render more than twic faster if you have a dual versus a single...

[AJLynn]

How well the dual CPUs get used depends on what you're doing. Rendering, yes, most renderers will use both processors and it will be approximately twice as fast. For your render farm, you should be able to have all the CPUs in all the machines going at once, and you're not going to notice all that much difference between types of CPUs, so optimize it for most total ghz within your budget while still having enough RAM. Modeling, I think most of what I've tried has run on one CPU (but it's not as CPU intensive as rendering anyway). Photoshop... I think the newer ones do use both CPUs for some of the more intensive functions. But since your render farm is rendering, so go with dual.

[Ray]

Is the assignment of tasks automated by the OS or can different tasks be assigned to separate cpu's manually?

[AJLynn]

You can do it manually, there's a function under the task manager called affinity, but it only lets you check off which CPUs a process is allowed to use - what I'd really like is a way to set it up so a given program really has an "affinity" for one CPU or the other - so it will prefer one, but if that one's loaded it will go to the other. (Anybdoy know a way to do that?) You're not supposed to have to do that but sometimes Windows is inefficient and I'd like to be able to do it manually.

[ihabkal]

wait till the dual cores are here and then you have 4 cores to select which runs which software. shweeet!

[radioVOY]

thanks a lot for your posts!

I'm going dual!

[Michael-k]

I have seen somewhere that the second cpu you will only get about 30% out of it, its that true ? If it is i cant belive that 2 2.8 cpus it twice faster than a single ?

[STRAT]

I have seen somewhere that the second cpu you will only get about 30% out of it, its that true ? If it is i cant belive that 2 2.8 cpus it twice faster than a single ?

 

depends what software you using. c4d render times on my dual 2.8 are certainly twice as fast as my single 2.8. if not more.

[Michael-k]

Okay dont belive it was C4d they was testing that time then