Issues with GTX280 and Mandelbrot

Thanks. Are you able to add another GPU to the system such that the GTX280 is only used for CUDA, and not display rendering?


Yes this is possible. I already added a 8800GTX to the existing setup. Till now i use the 8800GTX for CUDA calculation to continue with the development. I will change my xorg setup tomorrow in a way that the 280GTX can be used for calculation only.

Is there a particular test i should run?



done… same problems as before. Mandelbrot again freezes the XServer. Just change the color, zoom and pan a little bit and the fun is over again (fast in every sense). The only positive thing is that with our programs we sometimes get an undefined launch failure instead of a hanging X. But in fact this does not make the situation much better…

The setup did not change except the 8800GTX as device 0 for display rendering of course. Mandelbrot was adapted in a way that cuda uses device 1 (the 280GTX) for calculations.

Any further suggestions? In my optinion everything still points to a bug within CUDA 2.0b2?


I played around with my 2 cards setup. It turns out that also the 8800 GTX freezes when Mandelbrot is compiled with CUDA 2.0b. It takes much longer till the XServer hangs but still it is an issue because the stuff should run longer than just a few minutes. I appended a log when a freeze happens with the Mandelbrot application with the 8800GTX as cuda device.




From your bug report, it looks like you’re running both X and CUDA on the 8800GTX while the GTX280 sits 100% idle. Are you certain that you’re using the 8800GTX for X only?

I just tested with a cudaGetDevice within the fps calculation of the Mandelbrot application. Therefore it returns device 1 which is the GTX280 in my setup.


Does nobody else have problems with the new cards in combination with CUDA? Since we can reproduce the error with different setups using CUDA Toolkit 2.0 (Win/Linux, 32/64-bit, 8800GTX/GTX280 and all variations) with an SDK and with other algorithms, i do not think it is a problem with our specific setup.

Would be great if anybody could report about experienced behaviour too.


I’m not able to reproduce any stability problems with Mandelbrot using 177.13 and a GTX280.

Were all of your tests using the same motherboard?
Have you verified that you’ve applied the most recent motherboard BIOS?

We tested the algorithms on three different systems with three different motherboards (Intel & Nvidia chipsets). I also installed the most recent bios updates, but the problems still remain.


Could you try to lower memory/core clock by 20-40% and try again?

I lowered all clocks by 30% … the programs still crash.

As I already reported, cudaGetDevice is useless, it reports whatever you last passed to e.g. cudaSetDevice, regardless if it works or not. For me a more reliable method was to look at the GPU temperatures with nvidia-settings.

I looked at the temp too and the right one was bound to the CUDA stuff. Maybe this is important and i did not mention that before: We use a EVGA FTW card. Don’t konw if there are some known issues with specific cards? But normally EVGA knows what they are doing?



It does not work with a GTX 280 from ZOTAC either …

Still the same behaviour on all our machines and no idea what causes the problem. When does the stable version of CUDA Toolkit 2 gets released? Hopefully we can use the new cards then?!


I am getting some freezes also with Windows XP Professional 64 Bit, 177.35 driver, Cuda SDK 2.0 beta. Hardware is nVidia 8800GT

The Mandelbrot demo stops updating its display window, although the window title still updates the FPS numbers. This occurs randomly, after some seconds of zooming and panning in the fractal.


We have the same problems with linux (Asus GTX280, 32bit linux, 177. 13 driver, cuda 2.0beta) and the mandelbrot example, all other examples work fine.


We did some tests with the currently released display driver (177.41) within windows (32bit) and encountered much more stable applications. Mandelbrot does still lock up the computer but still our programs seem to work with the new drivers. Just for everybody having problems -> try the current windows release of the display drivers and report if the problems are gone or not.

As our development is mostly done on Linux we are very keen on seeing an updated and more stable version for the display driver there. At best for Ubuntu 8.04 ;-). So enough for the wishlist and we hope that our work can finally be tested on the new cards.


Ah yes one last question: Why is the display driver version not consistent on the different sites? gives for Win XP the 177.41 and on the 177.35 is suggested.


We installed the new drivers and cuda 2.0 and everything seams to be ok now. At least our programs are running stable with the new toolkit. I did not test the Mandelbrot example but i’m more interested in seeing our programs work…


I’m curious to know what has come of these issues since you last posted. Did the new drivers and cuda 2.0 fixed these problems for everyone or not?

I am having similar problems with a GTX280 in 32-bit LINUX using driver 177.67 and CUDA 2.0

X will lock up with some of my programs and with the Mandelbrot example. Before locking up, the CPU % that xorg is using goes crazy.

I’ve also had similar issues with a similar setup (same card and drivers in linux).