Assuming you mean to ask if I switched to non-hyperthreading mode, not yet.
I did some research over the weekend and have yet to come up with anything negative. Out on microsoft forums and tech forums I see people are reporting sucess with their versions of this problem: claiming performance increases with single thread programs.
Put it this way: if dividing a 2GHz core in half to do "hyperthreading" did not result in a performance decrease for any single "thread" (or core) then where is the genius who has managed to divide a processor by, say, 4 or 8 or 16.... how about 128 or so?. Nothing like a 256 core processor, uh? I think not. I'm no Solomon, but dividing the baby seems like a great way to get half a baby, or in this case, half a processor.
I have a customer who has done this for Inventor and reports an instant performance boost. They thought their new machines were junk until someone pointed out Inventor was running on half a processor. Many minutes to edit a complex pattern turned into just a couple.
So unless someone comes up with a good reason not to, I'll be looking into this and implementing it this week*. Once satisfied I'll advise my clients to do this, or at least try it on a problem "new" work station.
I have also read that some manufacturers make it harder to modify the BIOS and turn off hyperthreading. Also, as of now, I don't know where to begin on my machine. More research. It should be simple once I find it.
*YMMV, your mileage may vary, use caution any time you mess with how your computer runs.
Just an update from my experience on the issue of lagging after entering commands.
Having been convinced the issue lay with the network installation somehow, I've been trying to systematically eliminate possible causes for the lag we've been experiencing. I've tried moving and repathing everything I could think of to the local drives, but was having no success in eliminating the lags.
What I found seems to point at the network license server or the network license manager.
Basically, by 'borrowing' one of the network licenses shared by the users in our office and holding it on the local machine, the lags have pretty much disappeared (there's still a few). It seems when Autocad is installed with a network license, at least in a Windows 7 64-bit network, the software is regularly communicating with the license server while the Autocad session is running. In our case, and it sounds like possibly many others, the network license server, or manager, cannot keep up with this constant verification by all the machines in the office.
Not exactly a solution, but it's something. I don't really want users borrowing all the licenses as I know this will eventually start creating problems when they don't get returned in a timely fashion. I'll need to talk to our IT guys regarding the server speed.
Hope this might help some of you anyhow.
Thanks for the update, I would suspect this problem is more pronounced when the license server is busy with other stuff, or the network is somehow slow. In this case, AutoCAD's licensing is merely the canary in the coal mine of data flow and shows the problem because it's more.. senstive.
Here's my update:
I have a brand newish Dell XPS laptop. It has all the bells and whistles, barring one: I cannot turn off hyperthreading. So my 2GHz processors are running at 1GHz. (4 cores @2GHz x 1/2 for hyperthreading = 8 cores @ 1Ghz).
I called Dell support and after a week got the BIOS developers on the phone to confirm there is no switch in my BIOS to turn it off. So I am stuck with a single slow processor for Inventor and other single threaded programs.
This is a huge problem for busy professionals looking at purchasing new hardware and using published specs. Now I would advise very differently in this regard. It's also a step backwards in my opinion. I've run computers with much faster processors for 10+ years, and now my "modern" machine is essentially hobbled by design. The only solution is to buy much more expensive CAD built machines, or buy from sources that can verify prior to purchase whether or not things like hyperthreading can be turned off.
On the plus side, since Inventor renders with all the cores, I can generate animations and huge renderings very quickly.
We recently had this problem at our office, but it was because our company was aquired by a larger company. So when we switched to their servers is when the "hang ups" ( I call the blue wheel of money waster) started. Slow to startup, mistype commands, certain commands, all caused hang ups. After talking to one of the CAD techs. They figured out the problem for US and everything runs a lot smoother now. This may not fix yours but could be the problem.
I don't have exact details. But, registry had to be reset for the local user. I believe this was because when the switchover happened the new company stores mydocs for every employee on the server, but our office is not setup for that yet, because our storage is not setup for it locally yet. So the mydocs was looking at their network which is about 700 miles away.
So looks like it could be registry reset and/or having a mydocs folder either set locally or if network at least network that is local.
Also it could be that CAD is pointing at a invalid mydocs location, which autocad for some reason searches for even though no pathing is directly linking there.