2 Smaller Graphics Cards Or 1 Big One?

Hey there all, looking to update either my work’s mac or pc with a graphics card to render in Blender’s Cycles renderer (since I’m relying on the CPU at the moment and want to use GPU).

So since Blender’s Cycles only supports certain Nvidia cards I guess I have these questions:

  1. Would 2 smaller graphics cards be better off for faster rendering compared to one large one, eg would 2 GTX570’s be better than one Titan in regards to rendering speed and cost?

  2. Since my mac is my main work computer could these kinds of graphics cards be put into it, if it’s a:

Model Identifier: iMac12,2
Processor Name: Intel Core i5
Processor Speed: 3.1 GHz
Number of Processors: 1
Total Number of Cores: 4
L2 Cache (per Core): 256 KB
L3 Cache: 6 MB
Memory: 8 GB

whereas my pc is:

ACPI Multiporcessor x64 based PC
Intel Xeon CPU
2.26 GHz
NVIDIA Quadro FX 1800

  1. Does anyone else have a similar setup and could recommend me graphics cards to render from GPU in Blender’s Cycles?

Thanks in advance.

If you get a large single-card design like the Titan, then you will tend to get benefits in terms of reduced power consumption and heat production per flop of performance and (perhaps), better fail-safe systems designed to prevent the card from overheating.

Two smaller cards in contrast may mean more performance, but it all depends on whether you would prefer to take extra measures like watercooling and a larger PSU (not to mention the possibility of your work room getting toasty).

While its not necessarily the same, I picked up a 15" lenovo y510p with two nvidia gtx 750m cards (SLI) totalling 4gigs of memory and it renders extremely fast in cycles, the only other GPUs I can compare it to is a firepro and another GTX 560ti. I went with the sli based laptop to cut down on electricity consumption and noise, it does the job perfectly.

Two GTX 760 are as fast as one Titan, cost less but you have only 4 GB VRAM and you need a bigger PSU.
IIRC you cant change video cards in IMAC unless you are a brain surgeon. :slight_smile:

Cheers mib.

Ok thanks guys,

so from all the posts I’ve read so far here’s what I’ve discovered…

No to the mac in regards to 2 graphics cards or fitting in a card of my choice (unless I maybe wait for the MacPro).

For my PC I need to check a few things, like do I have 2 PCI Express x16 length Slots to hold the cards and a good enough PSU (since dual cards might overheat), and is my CPU a single, dual, quad core?

I’ll try to get a photo inside my PC, but the damn thing is locked shut thanks to the uni I work for. But here’s a few screenshots of my setup…



The other option is make a render farm or use a online render farm service.

Another question too is can CUDA in Blender use SLI graphics cards, cause I’m getting mixed reports…