Vista 64-bit speed...

Mikael wrote on 9/25/2008, 8:21 AM
Hi.

This is not a question of a problem but of the difference in speed between 32-bit and 64-bit.

I used to have Vista 32-bit installed on my AMD X2 6400+ / 2 GB RAM and nVidia 6500 computer. It took 6 hr 30 min to render about 60 min of video to a SD Wide PAL AVI file. And the computer couldn't show preview in realtime, so I bougt 4 GB RAM and a nVidia 9800GT card and installed. Now it took 5 hr 30 min to render the same video.
And with 32-bit, only 3 GB RAM is accessible so I installed 64-bit Vista instead to access all 6 GB RAM.
I had continued to edit the video now 1 hr 30 min. And render...
2 hr! What?
With 64-bit Vista it renders, almost, in realtime!
I then tried to install 32-bit Vista again to see... Yep. 5 hr 30 min for 60 min of video.

I have been working professionally with computers since 1994 but I have never seen such a dramatic change in speed with almost the same hardware.

This is very nice, so I do NOT complain, but could anyone tell me how this change in speed is possible?

When I run 32-bit a render took about 75% of both cores and 2,5 GB RAM. So, it seems that Vegas Pro doesn't need more than that, so the 6 GB RAM cannot be the answer. Not the graphics either, if Vegas Pro doesn't use the GPU?

Mikael

Comments

Himanshu wrote on 9/25/2008, 11:38 AM
Mikael,

When I run 32-bit a render took about 75% of both cores and 2,5 GB RAM. So, it seems that Vegas Pro doesn't need more than that, so the 6 GB RAM cannot be the answer. Not the graphics either, if Vegas Pro doesn't use the GPU?

It's not that 32-bit Vegas "does not need" more than 2.xGB of RAM; but rather that 32-bit apps are limited to 2GB of memory address space by Windows so that Vegas really isn't able to use more than that.

To test this you should measure the RAM usage during the 64-bit render process. My gut tells me you will see high usage, and the difference then may be that in the 32-bit render the data is being written to (and read from) the disk when 2GB of memory address space is used up, but in the 64-bit version you're able to use upto 6GB of RAM (your physical max, less available to Vegas) before it has to go to disk.
Mikael wrote on 9/30/2008, 2:32 AM
OK, I know that.
32-bit can address 3 GB of RAM, how much that is accessible to other software, I do not know.

I cecked this again and found that in 64-bit Vista Vegas uses some 350 MB RAM while render (On my system, no changes made to Vegas settings) and still uses some 75% of both cores.
Still, Vegas render in almost realtime on my system and it did not when I used 32-bit XP or Vista, still with the same hardware and settings.

When we set up SQL-servers at my work (Oracle, MSSQL and MySQL) for some of our customers (This is not Vegas! Just to compare) and upgraded the RAM from 4 to 8 or 12 to 24 GB, it speeds up, but not in this way.

I do not know how well programmed Vegas is using RAM and threads and all, but I still don't get it to add up, really. It is a too big difference.
Yet, a good such, but...

And why does 32-bit use total of 2,5 GB RAM on render (Do not know how much Vegas use) and on 64-bit 2,2 GB RAM? And still this difference in speed.
Terje wrote on 9/30/2008, 3:46 AM
Honestly, it makes no sense whatsoever. There is nothing inherently faster in 64 bit computing than in 32 bit computing. In many cases 64 bit can be a tiny fraction slower on some operations and a tiny fraction faster in others. This type of speed-up would only make sense if the software needed oodles of RAM and it could now address it directly rather than swapping to disk. It doesn't seem to be the case here.

Would love to see this reliably reproduced.
essami wrote on 9/30/2008, 4:32 AM
Mikael, what version of Vegas did you use?

Sami
rmack350 wrote on 9/30/2008, 7:29 AM
Okay, an application in 32-bit windows is supposed to get 2GB of virtual address space to work in. That's RAM plus page file. My guess is that 8.1 is getting more actual real ram and less page file.

Rob
Himanshu wrote on 10/5/2008, 8:43 AM
Here are two articles on Microsoft's web site about how much memory a process can access:

Memory Limits for Windows Releases

RAM, Virtual Memory, Pagefile and all that stuff

Like Sami, I'd like to know the versions of Vegas used by Mikael. Hopefully it's 8.0c under both to make a better comparison.