Topic: Working with (vitual) dual processors

[Amsterdammed]

My new computers (at home and in the office) seem to split the processor into two virtual ones.

It seems that Acad 2002 has some Problems with this fact. I remember in earlier day  that when I checked with Alt Ctrl Del the performance of the CPU it was at 100% when it was realty busy. Now it is 50%.

I think to remember that there was a system variable to set for working with dual processors. Does anybody know about this?

[whdjr]

I don't think there is a variable in AutoCAD to change; however on boot up you can go into the bios and turn off Hyper-threading.  Another way would be to go to the task manager, then the processes tab, then find the Acad process and right-click.  Then left-click on Affinity and then uncheck everything except CPU0.  This will make it only use the first cpu; however this is not permanent and will reset on reboot.  There is a website that shows how to set the affinity of a process that is permanet, but I can't find it right now.

[Amsterdammed]

you can go into the bios and turn off Hyper-threading

I'm not familiar with that stuff, so what influence would this have on the rest of my programs

[whdjr]

Instead of the machine thinking it has 2 processors it will think it only has a single processor.  Under most conditions Hyper-threading has shown little if any improvements and in some areas it slows the system down.  If your having problems with it I would shut it down in the bios.

As far as other programs go, most of them are not threaded programs so they will not even not it.  Windows XP, if that's what your using, will slow down a little because it recognizes multi-processors and can use them.

To enter the bios just restart the system and watch the screen for a prompt to enter setup, usually F1 or Delete.  In there just look around for Hyper-threading and it will allow you to turn it off.

[ronjonp]

WHIPTHREAD

Type: Integer
Saved in: Registry
Initial value: 1

Controls whether to use an additional processor (known as multithreaded processing) to improve the speed of operations such as ZOOM and PAN that redraw or regenerate the drawing. WHIPTHREAD has no effect on single processor machines.


0 No multithreaded processing; restricts regeneration and redraw processing to a single processor. This setting restores the legacy behavior of AutoCAD 2000 and previous releases.

1 Regeneration multithreaded processing only; regeneration processing is distributed across two processors on a multiprocessor machine.

2 Redraw multithreaded processing only; redraw processing is distributed across two processors on a multiprocessor machine.

3 Regeneration and redraw multithreaded processing; regeneration and redraw processing is distributed across two processors on a multiprocessor machine.


Note  When multithreaded processing is used for redraw operations (value 2 or 3), the order of objects specified with the DRAWORDER command is not guaranteed to be preserved for display but is preserved for plotting.

[whdjr]

I don't think he has that system variable in 2002, but I may be wrong.

[ronjonp]

I believe that WHIPTHREAD was introduced in 2000i.

[whdjr]

I believe that WHIPTHREAD was introduced in 2000i.

Hence the reason I couldn't find it in my 2000 version.

[Amsterdammed]

Thanks gentlemen for the help.

Ronjonp was right, it is as sysvar at least in A2002.

I typed it in and obviously an application we work with already set it to 3. Bummer, no improvement.

What I still don’t get is the fact, that when acad is really busy, it never shows the 100% use of the CPU (I’m working with XP PRO, SP2) like my old computers did.

It goes to max 60% the rest goes to System IDLE Process? Is that ok??

Thanks,

Bernd