Now we all know that a hyperthreading cpu can run two instances , and we know that a dual core can run two instances, BUT if you have a dual core hyperthreading cpu , in theory , shouldnt you be able to run 4 instances???????

I asked this same question over at the ENEMY ENCAMPMENT **GruntVille** , and although I dont really feel like researching it tonight, figured I'd put it out here too and see what some of y'all thought.

My head hurts now........

A little off track but I thought you could run up to 4 instances on even a single cpu.
It just comes down to bandwidth.
So I guess what you mean is, can you run 4 instances at 100% on a dual core HT cpu.

Im going to guess that it'll come down to memory demands spread across the 4 cpu's.
as in ,you better have at least 2 gigs of mem for that.
and a sweet cooling system to handle that load.

Ok, as I understand it: Hyperthreading WILL allow for two instances to run, but you acutally lose enough bandwidth for the single core that you don't really see an increase in production. You are actually throttling the single core with too much work in this case because of how intensive folding really is. The Pande group actually suggests that you only run one instance per actual core because of this. From what I read on the official forums, it seems that the point total using both methods is about the same.

So, you COULD run four on a hyperthreaded dual core processor, but I'd allow the extra production to happen and only put one instance per core.

But, that's my personal understanding and since I'm an AMD man, the HT aspect won't come into my folding experience. Others who have more experience and a better understanding of it may be able to prove me entirely wrong.

D

Edit:: Ok, I just found my own misunderstanding . . . I was wrong as to why Vijay Pande wants us to not use HT . . . He expains HERE that apparently is causes the runs to not be as thorough. That link leads to another link where they actually describe the science properly.

So, as Vijay said, if you only care about points, then run HT . . . If you are trying to help out people and push along the science, only run one instance per physical core.

D