I had the same problem,

Try to underclocking your CG.

(even i you never OC your CG, some constructor sold them a little OC)

download Ntune:

http://www.nvidia.com/object/ntune_5.05.54.00.html

For me it works fine with this tweak:

I decrease the core bus: 600Mhz -> 567Mhz
And the Memory bus ...

Octane need internet to start? Every time? Is that right?

What solution do you propose for people who have a production computer not connected?

Here a some octane device info:

GTS 250:
Global size memory = 511MB
Multiprocessors = 16
Cores = 128
8 core/processor
Clock Rate = 1801MHz
Shared Memory/Block = 16KB
Registers/Block = 8192
Warp Size = 32
Threads/BLock = 512

GTX 260:
Global size memory = 895MB
Multiprocessors = 27
Cores = 216 ...

You find the answer pixelrush! it was the overclocking!

(I never OC my CG, it has been done by the constructor)

So i download Ntune:

http://www.nvidia.com/object/ntune_5.05.54.00.html

I decrease the core bus: 600Mhz -> 567Mhz
And the Memory bus: 1050Mhz -> 999Mhz

Octane render see the clock ...

OK i did the right test, i exchange my GTX260-xt-oc with the GTS250-xt-oc, i did a new installation Xp sp3, last classic nvidia driver (260.89_desktop_winxp_32bit_international_whql.exe) And it works fine!

So there is definitly a problem with physX and cuda with my card... Just like the GTX470 you ...

Never the less when using one card on its own running Octane preoccupies the card and the UI display doesnt get updated properly
I think this is not the problem, because when my PC freeze, 30s later i have the blue screen of death (nv4_disp)...

Also, i try octane demo with an other computer ( C2D ...

Hi,
I don't play with the node or anything else, i just fly in the 3D view with the sample scenes.
And it crash even if i let it render...

Hello!

Here my config: Q9400 2.8Ghz - 8Go DDR2 - GTX 260-XT OC - Fortron 700W
FRESH XP SP3 32bit installation
cuda 3.0 driver and octane demo ( that's all , nothing more)
When i run Octane demo, it totally crash my PC after 1 or 2 minutes, and i have to power off manually...

I can play crysis ...