Hyperthreading or dual core

I haven't tried dual core yet, but my extensive testing with hyperthreading on or off was mostly inconclusive. I tried it with various other apps running, a couple sessions of SW, XP32, XP64, etc, and I didn't find any combination that said I should surely have it on or off.
I would think that for a given clock speed, dual core would work better because you have 2 complete processors running at that 3.2 (or whatever) clock speed..
WT

SW very rarely uses more than one thread, unfortunatly. Especially for me: I spend lots of time watching one of my 4 cores go at 100% with the other 3 sit idle.
Go for a single processor and disable hyperthreading for maximum single processor speed.
Phoxie skrev:

Go for a single processor, dual core, with hyperthreading turned off. That would be my recommendation. The cost of dual cores is now on par with single core chips, plus the power/heat savings that go along with more advanced chips. Although SW will only use a single core, your second core is free to surf the internet while waiting for a rebuild. It's kind of like hyperthreading but without limiting each "processor" to 50% of its parent's total capability. On a somewhat similar note. I'm going to attend a seminar on high performance computing later this month. I have an analyst at my office that has done extensive work and testing on parallel computing where he has forced a single threaded process to use multiple CPUs. First test was to use both processors on his dual processor machine. Positive! His second test was to utilize both processors plus a parrallel computer on the network. Test started positive, but he had to stop it short of official confirmation due to "real work getting in the way! His final test will be to utilize a processor farm of 4 dual processor computers. I bring this up because it may be possible to force SW to be multithreaded.
How much does SW benefit from a Dual core processor compared to a Pent.4 processor with hyperthreading?
I've seen some 17" laptops with Pentium 4 and hyperthreading and dedicated video that really rock and cost a lot less then similar laptops with dual processors.

Dual Core.
It is overkill that helps in certain circumstances whereas hyperthreading is limiting.
Phoxie wrote:

I am running a dual core 28. I havent seen a perceptable speed increase in SWX however there is a big increase in Photoworks speed. Both processors hit 100% usage while rendering.

I would like to thank everyone for responding to my question.
In summery it seems that if all things being the same, if I can get a dual core for the same price as a Pent.4 then get the dual core but if there is a significant difference in price between the two the get the Pent.4 and stick the savings in my pocket.

Our tests with hyperthreading showed a marked performance drop. Based on what we saw, we turn it off. But those tests were run two years ago - I don't know if things have changed. Frankly, I haven't thought to re-run it until now. However, if Wayne saw no difference, I have no reason to doubt (that dude's pretty throrough)
We have no dual core machines yet, but ALL of our machines have two processors. This is handy - SWx is crunching linearly on one processor, switch to email/research/writing reports/time sheet on the other. Its good to multi-task.
Of course, PWx uses two processors, so if you are doing renderings, go for it (I assume multi-core = multi processors)
One thing we have found useful is having one guy work two machines, either through KVM switch or remote access (don't know the geek term, but basically I can switch between controlling two seperate computers from my main system through the network). Again, we get to multi-task. Good to have when working PWx or Cosmos. Why have a talented guy sit there watching a progress dialog when they could be helping someone else out? However, that makes billing tough. The time itself is simple, but do we have to put an asterisk next to the job entry so they know they shouldn't use this as a benchmark for all jobs because we were able to do two heavy-processing jobs for different clients at once? We just let out clients know they got a break THIS TIME and we will try our best on the next job (with no guarantees - there are only so many computers) and they seem to understand and appreciate it.
Ed

I have seen a fair increase in speed using a dual core. Depending on what types of work you're doing, you *will* see the second core getting used plenty. On several models, I was seeing from 20-80% usage on the second core. A while back I ran a comparison between a fast single core (Athlon fx57) desktop and a reasonably fast dual core (Athlon 4800) laptop. The results were posted here, searchable through Google. It was about a toss-up, but the laptop in this situation was significantly less expensive than the desktop mainly because of the lower processor price.
Duals will beat singles in opening assemblies and drawings, in addition to FEA and rendering. The dual also performed better than the single when there were multibody parts, (which typically covers surface models, since surfaces tend to create more bodies than solids in default usage).
So in addition to the performance benefits, there are also the multi-tasking benefits others have mentioned. I think a dual core is a no-brainer. I haven't researched it in several months, and I know things change very quickly, but my understanding was that to get one of the new Intels (Extreme) that rivals the AMDs was a pretty expensive proposition. Again, I don't know the new models, but whatever the new equivalent of the 4800+ is should be a great value.
Good luck.