Can I run a gtx 1070 on a tier 2 power supply?
So in my system right now i have core i7-6700 and a 1050, I finally saved up the money to buy a 1070 when prices come back down so i was wondering if i can run it off my seasonic s12ll 350 watt psu. I saw that the s12ll power supplies are pretty good but i'm not sure if it'd be good enough to run a 1070. Can i go for it or should I upgrade the power supply to something better and wait a bit longer before upgrading to a 1070?
The Seasonic models are indeed a quality PSU. But the 350W version you picked is too tight for the components you wish to run, without any headroom for efficiency or upgrades. The S12II-350 only provides 324W (or 27A) at the +12V rail and only has 1x 6+2 pin PCIe power connector.
The GTX 1070 is a low-powered 150W-TDP GPU and your i7-6700 is also a non-OCable 65W-TDP CPU. Add your other basic components like MB, RAM, HDD/SSD, fans, and cooler, and you'll be looking at a power draw of close to (or beyond) the PSU's rated 324W limits already. Not to mention, the actual GTX 1070 model you will select *might* require a 6-pin and 8-pin PCIE power connector (though some models only require a single 8-pin).
If I was in your position, I'd be looking at the Seasonic S12II-520 or the Seasonic M12II-520 EVO for better efficiency and headroom.
Even though that is a Seasonic and it can handle every single of those 350watts I would say you are really pushing it. No harm will come because that brand it good, but most likely you will trip the safety on it when going full load.
i7-6700 = 90-120(OC)Watts
1070 = 160-200 (OC) Watts
Motherboard + Everything else 100 Watts
You are looking at 350 even on the low end... I'm going with no.
You can pick up a cheap EVGA 600 or 700 for $35 on amazon. I'm using both (2 computers) to power a 1080Ti 24/7 for compute tasks. Its cheap but it has enough headroom for really any single card setup.