Way back when an i5 could drive a trio of GPUs.
"Our tests demonstrate fairly little difference between a $225 LGA 1155 Core i5-2500K and a $1000 LGA 2011 Core i7-3960X, even when three-way graphics card configurations are involved. It turns out that memory bandwidth and PCIe throughput don't hold back the performance of existing Sandy Bridge-based machines. "
http://www.tomshardware.com/reviews/gaming-cpu-review-overclock,3106-4.html
If you can pull off the 1070 that's about the pinnacle of GPUs today.
http://gpuboss.com/gpus/Nvidia-GeForce-GTX-1070-vs-GeForce-GTX-1060
The move from 960 to 1060 is a step up, but I can't guess why the 960 won't do today. That is, do you really need ludicrous mode?
I currently have a gtx 960 2gb ssc and I have found a way to raise 476 dollars
I am not able to decide whether to buy a GTX 1070
OR
a gtx 1060, few steam games and a EVGA 700B PSU
Also I would like to know if my PC will overall bottleneck a GTX 1070
here are my specs
I5 4460 3.4 GHZ
EVGA GTX 960 SSC 2GB ACX 2.0
Crucial Ballistix Sport 16 GB RAM DDR3 1600MHz
EVGA 500W 80+ plus
MSI H97 PC mate motherboard
Corsair 100R Case
WD Blue 1 TB
Thank you !

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