Strange slowdowns in performance

[Reiko]

I recently upgraded my graphics card from a GeForce 9400GT to a GTX 560Ti and now some addons slow celestia down so much that it almost freezes.
Strange thing is celestia will run smooth for the first few minutes but after viewing several addons it will slow down while viewing some of the addons. Restarting my computer is the only thing that seems to help. I never had this problem with the 9400GT and I am using the latest graphics driver from the nvidia website.
Any ideas what could be causing this?

[selden]

I'd guess there's a bug in the drivers. There are a lot of complaints on the Nvidia forum about the 540, for example.

Exactly what circumstances (Addons) seem to cause the slowdown?

If you haven't already, you might consider getting a GPU monitoring program.
I use gpu-caps-viewer, but I'm sure there are others. http://www.ozone3d.net/gpu_caps_viewer/

[Reiko]

Thank you for the link to GPU caps viewer. According to that when the slowdown happens the GPU is being maxed out. The mods this happens on is 64k moon from the motherlode but only if I'm viewing an object in orbit over the moon. It does not matter what the object is. The other mod it slows down with is one I'm working on that uses BMP textures.
My old card and new card use the same driver so I tried the older driver I had for the 9400gt and it still happened. Maybe there is something wrong with the new card.

[Fenerit]

Is the main power supply robust? GTX 560 Ti need lot of power. Its specifications says:

- Maximum Graphics Card Power (W): 170 W
- Minimum System Power Requirement (W): 500 W

[selden]

Thank you for the link to GPU caps viewer. According to that when the slowdown happens the GPU is being maxed out. The mods this happens on is 64k moon from the motherlode but only if I'm viewing an object in orbit over the moon. It does not matter what the object is.

I would expect this to be slow because as the orbiting object moves, Celestia has to continuously load more and more surface texture patches as your viewpoint passes over areas of the Moon that you haven't seen before. I would expect this to have the same performance as the old card because it is limited both by the disk (reading the new tiles) and the CPU (decompressing the images to their actual resolution and converting them into a format that the graphics hardware uses).

The other mod it slows down with is one I'm working on that uses BMP textures.

I would expect this to be slow, too. Celestia's support for BMP is not very good. Although the images don't have to be expanded to their true resolution, they do have to be converted into a format that the graphic hardware can display. I suggest converting them into DDS format if you want the best performance: that format is loaded directly into the hardware. No expansion or conversion is needed.

My old card and new card use the same driver so I tried the older driver I had for the 9400gt and it still happened. Maybe there is something wrong with the new card.

What isn't clear to me is if the fps is actually less than it was for your old card or if it just seems slow compared to the speed of other operations. I would expect image loading to be relatively slow, but performance to be "normal" once they've been loaded into the graphics card.

[Reiko]

Is the main power supply robust? GTX 560 Ti need lot of power. Its specifications says:

- Maximum Graphics Card Power (W): 170 W
- Minimum System Power Requirement (W): 500 W

I have a good power supply for the cart. 650W with 51 amps on the 12 volt rail. The card requires a minimum of 500W with 30 amps

Thank you for the link to GPU caps viewer. According to that when the slowdown happens the GPU is being maxed out. The mods this happens on is 64k moon from the motherlode but only if I'm viewing an object in orbit over the moon. It does not matter what the object is.

I would expect this to be slow because as the orbiting object moves, Celestia has to continuously load more and more surface texture patches as your viewpoint passes over areas of the Moon that you haven't seen before. I would expect this to have the same performance as the old card because it is limited both by the disk (reading the new tiles) and the CPU (decompressing the images to their actual resolution and converting them into a format that the graphics hardware uses).

The other mod it slows down with is one I'm working on that uses BMP textures.

I would expect this to be slow, too. Celestia's support for BMP is not very good. Although the images don't have to be expanded to their true resolution, they do have to be converted into a format that the graphic hardware can display. I suggest converting them into DDS format if you want the best performance: that format is loaded directly into the hardware. No expansion or conversion is needed.

My old card and new card use the same driver so I tried the older driver I had for the 9400gt and it still happened. Maybe there is something wrong with the new card.

What isn't clear to me is if the fps is actually less than it was for your old card or if it just seems slow compared to the speed of other operations. I would expect image loading to be relatively slow, but performance to be "normal" once they've been loaded into the graphics card.

I have discovered a lot of problems using BMP textures and am working on changing them. But what I don't understand is that with the old 9400gt these addons ran smoothly. With the new 560Ti they run smoothly at first and then later begin to slow down. It's as if the card gets tired or something later on.

[selden]

You should also consider what might be in the background at the different times. Although it shouldn't depend on the type of image format, having more objects in view causes Celestia to run more slowly while it determines which are being hidden behind what.

Sadly, another thing to worry about is the temperature of the graphics chipset. Working harder (displaying realtime 3D) makes them run hotter. If you haven't already, you might consider installing one of the temperature monitoring programs like SpeedFan http://www.almico.com/speedfan.php (That's what I use, but there are others.)

Some cards are really not designed to stay as cool as they need to be when they run continuously in 3D mode. As a result, they overheat and automatically reduce the clock speed in order to reduce the temperature. Nvidia even warns not to run their highest-speed top-of-the-line cards continuously in 3D mode. They'll draw too much power and cause the motherboard and power supply to overheat and have problems of their own. In their Web forum, Nvidia explicitly warns not to run the OpenGL benchmark program Furmark on those cards, for example. You don't have one of them, but still...

[John Van Vliet]

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[Reiko]

I'm beginning to suspect these problems have nothing to do with the graphics card. I ran celestia for 30 minutes continuously viewing different addons with large textures and no slowdowns. I then open firefox to view a few pages and switch back to celestia, suddenly the slowdown is there with one particular addon. I leave celestia running and close firefox, the slowdown is gone. I still leave celestia running and open firefox and the slowdown is still gone.

I can't make any sense of it but perhaps my processor is having issues or memory.
I think the next step is to load all of the addons I'm using onto my laptop and see what happens. My laptop has a better processor but weaker GC.

BTW John, isn't sync to display device the same as vsync?

[selden]

Current versions most Web browsers use the graphics hardware to accelerate the rendering of some types of Web pages, primarily video and animations. This might be interfering with Celestia's graphics. Most browsers also have an option to disable it.

A description of how to disable Firefox's hardware acceleration is available at
http://www.trishtech.com/internet/disab ... efox_4.php

[John Van Vliet]

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