Problems with virtual memory

[danielj]

It?s almost every time that Celestia is accusing that the virtual memory is too low.The page cache is set to 682 and the minimum to 384 MB.Every time this happen,Celestia almost crashes and work at low fps.What can I do?Should I change my video card?My processor?I have an Athlon XP1800 ,256 MB RAM DDR256,Geforce 4 MX 440SE.Or should I only raise the virtual memory?How much?I am using 4k textures for Ganymede,Callisto and Io.For Europa,I am using 4k texture,normal and spec.

[selden]

Both minimum and maximum sizes for the virtual memory file should be the same value, (about 1GB or even larger). This causes the file to be permanently allocated.

Then defragment the disk -- so that the swap file becomes contiguous, with all of its blocks in the same area on the disk.

When the minimum is smaller, Windows dynamically expands the paging file at runtime. This can cause extremly poor response, since the pieces it allocates will be at random locations all over the disk and not next to one another.

[danielj]

OK.Selden,but I would like to know what is the maximum page memory possible for an Athlon XP 1800.And what about put the system to mange the page memory?

[Harry]

Both minimum and maximum sizes for the virtual memory file should be the same value, [...]
When the minimum is smaller, Windows dynamically expands the paging file at runtime. This can cause extremly poor response, since the pieces it allocates will be at random locations all over the disk and not next to one another.

While from a performance-point-of-view this is correct, it's no solution for danieljs problem: probably it's better to have no upper limit (or a much higher one). I personally don't bother too much about system performance when it's paging to disk - it's slow anyway

Harald

[JackHiggins]

I've always left the virtual memory settings alone... (you're talking about System Properties>performance>Virtual memory - right?)

I'll try setting them to what you've suggested there, and see how things look! I actually defragged my disc yesterday- couldn't take that long to do again...!

[selden]

As Harry reminds us, having a large enough paging/swapping file only makes it possible to use large textures. By increasing it to, say, 2 or 4GB, you'll certainly get rid of the vitrual memory error messages. If Celestia really has to use the virtual memory, however, your system's performance is still going to be absurdly slow.

If you're running XP, run the Task Manager and watch the Performance tab's "PF Usage" chart. When the PF (Page File) use is greater than the size of your main memory, you will notice that your system becomes much slower.

You should consider putting as much main memory into your system as it can hold or that you can afford. 256MB is not enough if you like 4K and larger textures.

Also, use DDS textures instead of Jpeg or PNG. DDS textures don't have to be decompressed: they get written directly to the graphics card. Jpeg and PNG have to be expanded first: a 4K texture needs about 32MB. Several such textures add up quickly. (My understanding is that specifying the "Compress true" SSC option saves on main memory for storing them, but they still have to be expanded into the graphics card, which makes loading them slower.)

I hope this helps.

[Darkmiss]

I think that Selden is asuming you have windows XP
Virtual memory for windows XP is far more advanced than in 98 or ME

and as Selden said sould be set to 1024 or above in both minimum and maximum, in the custom size section.
Once you have changed it, dont forget to hit the SET button to make it work.

Do not let the system manage it

as for other operating systems, I cant remember back that far......

[Buzz]

Theoretically you should set the lower and upper limit to the same value of around 1 GB, but I got some "blank" planets as a result doing that, because it was still too small. It did work when I let windows decide what to do as a quick fix... So if you decide to set it to a fixed size, make sure you choose a high enough size.

I have WinME, 384 MB

[danielj]

I only can afford an additional 256 MB RAM and perhaps more 128 MB RAM,with a total of 512 to 640 MB of RAM.In this case,can I deal well with at least 8k textures?And what the influence of a video card of 128 MB,like Geforce 4 Ti or better?

[Guest]

I have read that the swapfile works best at a fixed size as it therefore cant fragment, and the size should be 1.5 times the ram, this comes up as the recommended figure on the settings tab. Dont know why though. I had a problem increasing the size of the swapfile, bluescreen etc.Maybe it was treating the file as protected? I had to to set the file to no paging file, restart, defragment and then set the new size. Just in case this happens to anyone....