What is best way to handle hyperthreaded dual-core in SB?

[jasong]

If you have a dual-core P4, is there a best way to handle hyperthreading? Would it, for instance, be beneficial(or even possible to set up properly) to PRP with both cpus and somehow apply hyperthreading to factoring or sieving?

Or would that handicap your computer to the point it's less efficient?

[vjs]

This has been discussed before and I don't think there was a really good answer.

If you only want to prp then you have to install the service with the -o2 <-- check the readme.txt option. For a single processor I'd say running two instances is really the only option when it comes to prp.

My suggestion... what i would do.

Since both prp and p-1 benifit the project, I would run the client with a regular install (i.e. one instance). I'd then install Prime95 to run on CPU1 (the second CPU) especially if the machine has 1G of memory.

One thing that I have never seen tested is as follows.

Install the client allow it to run at normal priority (this would make it consume 100% of the actual processor, the machine would be sluggish). Then experiment with the sse2 and cmov client (non-sse2) see if there is a speed difference on the virtual HT processor.

Choose the one that gives you the best speed for sieve and run that sieve client, see if the speed changes when you set the prp client back to idle.

(may have to reboot inbetween/not sure)

It would be an interesting test.

[jasong]

Note: I don't actually have a P4, but I like to come up with questions people might wonder about and give obvious subject lines.(since a search didn't answer the question)

[hhh]

There have been some rumors that combining different parts of the project would make the best use of an hyperthreaded proc. Myself has been contributing in propagating them.
Now I made tests and found out that actually combing the client with sieving does NOT give any performance improvement.
Running P95 with something else reealed to be quite impossible, the machine slowing down at a point not to be able to move the mouse anymore or one of the two consuming all the processor power; and running two times sieve or two times p95 was already known to be not more efficient.
The only way seems to be to run two times the client.
I have some problems with it, can somebody please post a serious investigation?
Thanks, Yours H.

[Mystwalker]

Now I made tests and found out that actually combing the client with sieving does NOT give any performance improvement.
Running P95 with something else reealed to be quite impossible, the machine slowing down at a point not to be able to move the mouse anymore

I don't have such problems at all, although I do this most of the time.
The only problem: When I e.g. start a video, it stutters from time to time. When I deactivate one of the two DC applications, the stutter is gone.