Titan Black only 1.8x as fast as gtx 560, why?

Hi everyone,

I just got an ASUS GeForce GTX Titan Black as an upgrade to my ASUS GeForce GTX 560 and yesterday I installed the Titan Black and started a render (cycles, CUDA) in Blender to see how much faster it is.

According to several benchmarks on the internet, the Titan Black should be at least 3x as fast as the GTX 560 (both not overclocked), but in my renders I saw that it was only 1.8x as fast as the GTX 560 (off course both with the exact same Blender settings).

I have GPU Tweak open and it tells me that the Titan Black’s GPU usage is 99%, wich is a good thing, but that the (GPU)Memory Usage is only 910MB (it has 6GB on board).

Also, when I render the 2.6x Cycles render benchmark (I can’t post URL’s because of the rules (I am new here), sorry), my Titan Black renders it in 55.05 seconds, a normal Titan does this in 29.47 seconds (both the same CPU (i7 2600)), while the Titan Black is an upgrade to the Titan.
This benchmark was made for Blender version 2.6, but 2.71 is actually faster so this can’t be the problem either.

I have my Titan Black connected to a PCIe 2.0 slot, but according to several gaming benchmarks this is not a big deal and decreases the FPS only with 1-4 FPS.

Does anyone have any ideas why I have these results and if I can do something to improve them?

Thanks in advance!

OS: Windows 7 home premium 64bit
CPU: i7 2600
GPU: ASUS GeForce GTX Titan Black
RAM: 8GB DDR3 Corsair RAM 1333 Mhz
PSU: 700 watt Cooler Master
Blender version 2.71 64bit

Just based on some testing I’ve done with my 750 ti, the performance you will see can vary wildly depending on the scene you are rendering. A few things to consider:

  1. Gaming benchmarks won’t tell you much, rendering workloads are very different.

  2. Memory usage is going to totally depend on your scene

  3. Make sure you’ve increased your tile size (at least 256x256)

  4. PCIe speed doesn’t seem to matter at all (I also have PCIe 2.0 slots and have yet to see utilization of the bus over 5% with Blender… i.e. PCIe 3.0 won’t help)

  5. Should you decide to overclock, the lions share of the boost comes from the GPU rather than RAM clock (makes sense since rendering is almost always compute bound)

@doublebishop

In cycles benchmarks the Titan Black is at least 3x as fast as the GTX 560.

I already looked at that benchmark and the spreadsheet. A normal Titan in there renders it in 29.47 seconds, mine does it in 55.05 seconds while the Titan Black is faster than the Titan and we have the same CPU.

@phil14

  1. First off, I didn’t look at generic gaming benchmarks, only with the PCIe 2.0 thing I looked at generic gaming benchmarks, that is why I explicitly said that they were gaming benchmarks.

  2. I already assumed that, thnx for the confirmation.

  3. I have exactly 256x256, I figured that was the fastest setting in my renders.

  4. Thnx for the confirmation.

  5. Thnx for the tip!