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tmon
12-07-2003, 04:45 AM
Curious that Aura on our Supermicro P4DC6+ Rambus system (dual 2.0 Xeon) renders targa file sequences to RTV files much faster than does our brand new Supermicro X5DA8 DDR system (dual 3.0 Xeon).

We are speculating that it is due to the difference in type of RAM.

Comments? Insights?

SBowie
12-07-2003, 02:25 PM
Interesting - how long are the sequences? I would expect that RAMBUS would provide some advantage (though I wouldn't have guessed it would be that much), but once your sequence duration means you are making heavy use of the temp file I would expect HD speed to be a big factor, too. Could that have a bearing?

tmon
12-08-2003, 02:48 PM
Mostly the sequences are only about 10 secs.

The Aura temp file is on the video RAID too, btw.

I would say that the renders (to RTV with Alpha) are taking at least %35 longer with the DDR RAM (I haven't done an actual stopwatch comparison test yet).

SBowie
12-09-2003, 07:23 AM
Hmmm - if you do any empirical tests, please update us. Do you see a similar effect with LW? It would be interesting to be able to isolate the RAM as the only variable. One might have expected that the faster front side bus speed of the newer unit along with the faster cpu's would more than compensate for the different RAM speed. And I suppose there may be other factors, like HT being on or off?

tmon
12-10-2003, 03:14 AM
Ahh yes...HT.

Where do I turn that on or off?!?! I'll have to check my BIOS settings, I guess....

What's the word on hyperthreading and VT[3] operations, btw?

SBowie
12-10-2003, 08:49 AM
There are a number of factors involved in HT, and whether it's available on a given system - you might start from here:

Intel's HT Home (http://www.intel.com/technology/hyperthread/)

Basically, the mobo, cpu and software all need the capability -- IIRC, this page leads to links that help you identify which chips and chipsets qualify.

tmon
12-10-2003, 12:18 PM
Thanks, Steve, I'll check it out!

satya
12-10-2003, 07:08 PM
It is possible that RAMBUS is making all the difference.

Taiji - do you have equal amount of RAM on both systems?

Even though the FSB may be higher in the newer motherboard, the memory bandwidth of RAMBUS is higher than that of DDR especially in the "burst" mode and the Intel Xeon uses this "burst" feature all the time.

Using DDR RAM with an Intel Xeon is just crippling the processor power. Just imagine that these very, very hungry beasts - 2 x Xeon 3.0 - must be fed all the time otherwise idle cycles start off ...


:cool:
Satya

tmon
12-10-2003, 09:02 PM
do you have equal amount of RAM on both systems?

Yes, we have 2GB of RAMBUS on the dual 2.0 Xeon P4DC6+ system, and 2GB of DDR RAM on the Dual 3.0 Xeon X5DA8 system.

I'm still looking into the HT issue - did I read correctly somewhere that W2K Pro doesn't do HT? We're running on W2KPRo on both systems...

There was a big backlash against RAMBUS because of their pricing, but it just might be that they DID have a superior product...

I hope others can chime in on this thread...