Upgrade with GTX 780ti for VRay RT ?

[reboot_89]

Hello I hope I won't be long:

I currently own a GTX 560ti 384 CUDA cores graphics card which I use with Vray RT for CUDA rendering, but sometimes when the ActiveShade window is running, the display lags almost to being unusable..

I am planning on upgrading with the new GTX 780ti graphics card (2880 cuda cures)

My MotherBoard supports two graphics cards, but My PSU has the capability to power only one GPU.

Here is my curiosity: Will the GTX 780Ti manage all by itself long periods of active RT rendering with No display lags? My other option is to keep the current 560Ti for display only, and the 780Ti for Rendering only, but that would mean to also change the PSU, which I could do without..

SO: swap 560ti with 780ti OR keep both cards and also upgrade PSU?

Thank you very much for your patience and support

 

[nubz]

howdy

I have just built a new PC specifically for rendering, i use Octane (also GPU based render engine). Im not familiar with Vray, but with Octane you can set the render priority of each video card in your machine. So if you have only one card, you can set the render priority to low or medium to reduce or cut display lag. If Vray does not have that option, then no matter what video card you have, you will get display lag while rendering, as the engine will use 100% of your GPUs resources, or near enough. Naturally, the render priority option in Octane will sacrifice speed for no display lag. So in my machine i run 2x GTX780s, for a total of 4608 Cuda Cores, keep them both on highest render priority for maximum speed, and i have both my monitors plugged into my motherboard's onboard video via HDMI cables. So essentially, while im rendering, i switch the monitors over to their HDMI channels, and turn off the displays out of the video cards in windows display settings, and viola - rendering at full speed with no display lag.

So if your motherboard does not have on board video, my advice to you would be upgrade your PSU to handle more than one video card, get your new 780Ti and use that for rendering, and run the display from your 560ti. Assuming Vray will let you set which video card it uses. And stay clear of SLI

 

[Bejusek]

From V-ray RT manual:
If you have only one GPU on your system, you may find that the user interface becomes sluggish and unresponsive while V-Ray RT is rendering on the GPU. To alleviate this problem, reduce the Rays per pixel and/or the Ray bundle size parameters in the Performance section of the V-Ray RT renderer settings in the 3ds Max Render Setup dialog. For example, you can try values like 128/8 or 128/4. This will break up the data passed to the GPU into smaller chunks, so that the user interface requests can be processed faster. Note however, that this will reduce the rendering speed. Turn on the statistics display to check the difference in render speed and to find the optimal settings for your system.

780ti has incomparably more processing power than 560, but it is still possible to flood it with so many data to process that it 'won't have time' to refresh your desktop. Try tuning this parameter mentioned above and see if the scene rendering performance is acceptable. With 780ti your renders would be much faster, but it costs a lot of money.

 

[reboot_89]

Hey, thank you for your quick answer

I have tried playing with the render setting but my 560ti can only do so much. So the upgrade with the 780Ti will definetly happen.. I was just hoping that this super-card would be so super that I wouldn't have to also change my PSU

anyway.. thanks again for confirmation ! 😀

 

[reboot_89]

Hey it's me again..

I was just pondering over the GTX 780 instead on the Ti version.. I know the Ti is better, but is it all that noticeable in Vray RT ? I can't find any numbers to justify the price diference.. Is the Ti worth it? I'm thinking that the jump from 560ti will be huge with any of the two...

 

[Bejusek]

Yep, Ti version is quite expensive. A normal 780 will be very significantly faster than your current card, but still few seconds slower than Ti. Other option to consider is 770, with 4GB memory, allowing you to render more complex scenes. I think it would be slower about 10-15% than 780.