gpu Performance increase from adding second GPU to my Rig

[eebling]

Hey, I took advantage of some of the price drops on GPU's lately with the release of the 20 series cards from Nvidia. I Got an evga 1070ti ftw2 card for 429$( also has a 20$ MIR to drop final cost to 409$). I put this into my machine that has had an evga 1080ti FE card in it since I built it a year and a half ago. I wanted to share the "real world" test results in case anyone else is wondering if it is worth it to pick up another card.

 The PC is running win10pro, 64gb ddr4 ram, intel i7 6850k 3.6ghz, primary drive is a samsung 960 evo m.2 ssd and a secondary crucial ssd, 1000 watt evga gold G3 psu, Houdini 16.5.268 and redshift 2.5.48 ( i think ) etc... 

I ran a redshift test on a scene that is a decent size pyro sim, rendered 60 frames at full HD with fairly hq setting. With just the 1080ti in the pc, the render took 38min17seconds. With the addition of the 1070ti, the render took 25min26seconds for the 60 frame sequence. Adding the second card took almost 13 minutes of the sequence render time. I would say it is worth the roughly $400 bucks. 

With the option of enabling/disabling gpu's in the redshift plugin options, I ran a single frame of the render and here was the result: with just the 1080ti - 26 seconds for the first frame. With just the 1070ti - 34s, with a little boost to the gpu settings on the 1070ti using the evga overclock software - 32 seconds( not enough for me to want to keep it overclocked beyond how it arrived). With both gpu's enabled - 15 seconds.

 I think I would be willing to buy another 1070ti while the sale/rebate is going on if it will reduce the render time a further 13 minutes. I'm assuming it would, but maybe I'm not adding something up right here. If adding one 1070ti to the machine cut 13 minutes off the render, wouldn't the addition of another 1070ti take another 13 minutes off the render time.? It would be incredible to drop the test sequence render time down from 38 min to 12 min for roughly $800 in hardware upgrades.!

 I ran all the PC's parts through a component checker online and even If I add a 3rd card, it should still have about a 100watts of buffer on the 1000w psu. Would probably want to add some more/better case fans if increasing the GPU count from one to three.!

 

Anyways, thats what adding an extra card did for me. 

 

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