P4 Hyper Threading: VDub grabs all power.

[KE]

I have just upgraded my PC to a P4 2.8 GHz with Hyper Treading and installed a new 120 Gig Maxtor 7200 rpm HDD.

Encoding with GK/VDub is great and fast (30-40 fps) Both threads are used, one about 100% the other about 80% to a total of 87%.

But…

Trying to use the PC for anything else at the same time is painfully slow.
With my old system I used to set VDub priority to Idle and use the PC normally. (Never mind that encoding took longer.)

Now opening another folder or program can take up to 25 seconds while GK/VDub is encoding. (XviD RC4)

The weird thing is: Once it has started I can watch a movie or even capture from my TV card without losing any frames.

I can see that WinXP handles the priorities OK with VDub running on low and everything else on normal. So this does not seem to be a CPU problem but maybe disk access?

Does VDub use up all the disk bandwidth?

What ever the problem, I as the user would like a faster response.
After all I am the one who paid for the system :)

Allowing VDub to use only one thread makes no difference.

I have tried to put the data GK uses on a second HDD. This made it a bit faster but not much.

I have not yet tried to put input and output of VDub on different HDDs.

Do you guys have the same problem? Are there any tricks?

Thanks, KE.

[jggimi]

moved to Vdub forum.

[TotalChaos]

This may be a part of your system that your not used too. When you upgraded did you upgrade the motherboard? If so, there will be diff IDE controllers. I have a similar system setup as you except I have a RAID 0 with dual 10,000RPM drives. Still there is a small pause when accessing drives. One last thought it could perhaps be your virus scanner if you have one. There will not doubt be a delay when access files while being scanned using the realtime scanner.

[KE]

Thanks TotalChaos.
For some reasons everything works perfectly now without doing anything.
Maybe XP has adjusted itself. It was a new installation. I suspect the slowdown was caused by pagefile usage? (I have 256 Meg Memory.)

I’ve tried with and without Norton and that makes no difference. Thanks again.

[Angelus]

Normally what I do when I'm encoding and trying to do something else on here I just set the affinity of VDub to one CPU and do whatever I'm doing on the other CPU. Granted I have SATA drives and I can't really tell a difference when I'm encoding and doing things and when I'm not. Just something else to try.

[KE]

Thanks Angelus, I've tried that when I had the problem and it did not help but encoding was slower. Now that for some reason everything works, I can let VDub use both threads and still use the PC normally. Encoding priority is set to low automatically (by GordianKnot I guess). I read elsewhere that VDub uses one CPU for input and one for output. The speed is amazing, especially without de-interlacing. Up to 60 fps on first pass and 40 fps on second pass.

[Asmodian]

A P4 2.8 GHz with 256Mb of RAM?! You would have a much nicer computer with another 256 of RAM, encoding speed would be basically the same but general responsiveness would be much better.

Sorry for the off topic post but it always pains me to see these high end CPUs choked by not enough RAM (and RAM is cheap).

[KE]

I went to the shop wanting to buy a faster Celeron CPU and left with a new Motherboard, P4 processor and 120 Gig HDD. I already tried to swap the 256 Mb for 512 but they were not interested. The reason I have not yet bought an other 256 Mb is because I only have two slots and knowing you guys, the next post will tell me 2x256 Mb is not enough:)

[TotalChaos]

Do you know what chipset your mothorboard has?? If your using a 7205(granite bay), 865 (springsdale), or 875 (Canterwood), you have a dual memory channel chipset. I'm guessing with only 2 DIMM slots you have the mainstream 845 chipset (single channel memory controller). Getting to my point, the dual memory chipsets would run much faster using two sticks of like size memory IE 2x256MB then with one 512MB stick. Also I just checked my system, which is currently encoding using virtuldubmod + AVIsynth, and it looks like the memory allocated is around 288MB. With that amount being used for encoding and assuming you have your OS running as it comes (with alot of MS services running and as most people do) you probably have anywhere from 175MB-220MB allocated to MS services and personal services (virus scanner, firewall, print services). This puts you pretty close if not over the 512MB limit. If you plan on running any other memory consuming app (perhaps photoshop or a video game) then 512MB of mem may not be what you want. Two last things, I personaly suggest letting virtualdub from gordian knot, which actualy uses AVIsynth to stream and is TWO single threaded apps (virtuldubmod + AVIsynth), use both threads of your HT P4 CPU. It will increase your frame rate! Not as much as I would like but still more then assigning it to only one. Secondly, see this thread http://forum.doom9.org/showthread.php?threadid=35153 . I've found it to contain more info about multi CPU, multi threading, Hyperthreading, and the virtuldubmod + AVIsynth combo then any other thread I've read to far on this forum. (also I starred in it..... yeaaaa.... but seriously it does have some good info)

[KE]

Thanks TotalChaos for the very clear and helpful post.
My Chipset is Single Channel. (SiS 661FX)
I am using Gordian Knot and find it works exactly as you describe. Using both threads is maybe 50% faster than using one only. Without de-interlacing both threads run at nearly 100%.