OTOY Forums

So (just to understand) as I my pc have 1 PCIe x16 and 2 PCIe x1 slots,
I can add one Xpander (with 2 GTX480) to each PCIe x1 expansion slot
and keep my GTX260 in PCIe x16... ????
and Octane benefit of all cards?

ycarry wrote:So (just to understand) as I my pc have 1 PCIe x16 and 2 PCIe x1 slots,
I can add one Xpander (with 2 GTX480) to each PCIe x1 expansion slot
and keep my GTX260 in PCIe x16... ????
and Octane benefit of all cards?

yes

Radiance

Wahooo
please EricNV, how much Shipment and VAT for France?
Note: here in France I can buy GTX480 for 490€ (include 19.6%VAT and free shipment)...

Hmmm, on Cubix site support, I read :

Connect as many Xpanders as you have available PCIe x 8 slots in the host computer

PCIe x 8 slots, not PCIe x1 ! This has to be confirmed, but it is written.

For what I have been told recently, the cable link transfer speed is not important during the rendering process, but it is much important during the loading of the scene.

I am currenlty doing a test on an animation of 35 frames of a scene requiring 290 MB of VRAM, on a GTX 260 mounted in a Cubix-Xpander which is connectet to a PCIe 16x 1.0 : For a rendering time of 4 seconds (at 32 samples per pixel), the loading time of each frame is 124 seconds ! More than 2 minutes per frame .

At this speed, the whole 35 frames animation requires 72 minutes of loading for 140 seconds of rendering !

For more samples per pixels, the ratio will decrease a bit, but not so much.

If you consider that the tested scene weights only 290MB, on a PCIe x 16 (even if it is a 1.0) the loading time(so, the transfer speed of the PCIe link) seems to be a very critical factor ! I doubt that PCIe x 1 are usable.

For what I have tested so far, my fears are confirmed and the current loading time for animation is really beyond what I consider as acceptable.

ROUBAL wrote:If you consider that the tested scene weights only 290MB, on a PCIe x 16 (even if it is a 1.0) the loading time(so, the transfer speed of the PCIe link) seems to be a very critical factor ! I doubt that PCIe x 1 are usable.

I'm not sure if it is the PCIe transfer speed that is the bottleneck. According to the specs, PCIe x16 1.0 has a transfer rate of 4 GB/s. That means that 290 MB should transfer in < 1 sec. PCIe 2.0 doubles the transfer rate (to 8 GB/s for x16).

There must be something else slowing it down.

PCIe x 8 slots, not PCIe x1 ! This has to be confirmed, but it is written.

But I read PCIe x1 connector card here:

our units here came with 8x PCI-E and they work fine.
i believe they have both 8x and 1x options.

You should be able to use octane just fine on a 1x PCI-E connection, you'll just have to wait a minute instead of 2-3 seconds for the mesh to appear when you first click on your meshnode.

Radiance

What about animations ? Currently, frames on a slight scene are loaded in more than 2 minutes each, not only the first one. Is it the necessary time for Octane to update the geometry ? Can't it be reduced ?

ROUBAL wrote:What about animations ? Currently, frames on a slight scene are loaded in more than 2 minutes each, not only the first one. Is it the necessary time for Octane to update the geometry ? Can't it be reduced ?

do you mean the loading/voxelising or the actual upload to the GPU when you click on the meshnode the first time ?

Radiance

I mean the loading/voxelising time.

For a still picture, it is done once, and after that if you spend time to adjust your materials parameters, you almost forget the loading/voxelising time, but when you have to render an animation, this loading/voxelizing time is repeated for each exported frame and then, it is another story : I have just finished rendering a 35 frames animation test, and while I got 2 to 4 seconds of rendering per frame at 32 samples per pixel, The loading/voxelizing time for each frame was 124 seconds... for a scene in 1024x576, with only a character in a empty screen (290MB).