Is this a reasonable assumption: for Kaby Lake builds with one 1080Ti a 650W PSU is sufficient or 850W for SLI?

I have an 850 with a 1070 card.

blaustern

 

57 minutes ago, Djang0 said:

Is this a reasonable assumption: for Kaby Lake builds with one 1080Ti a 650W PSU is sufficient or 850W for SLI?

Yup, it is a reasonable assumption providing you get a decent brand of PSU which will reliably deliver that power.

I have a Kaby Lake powered by a Corsair 650 Watt PSU with a RX480 GPU. Modern GPUs don't need anywhere near the overkill of power old ones used to require, which is why 650 is more than enough. I used to use 850 Watt PSUs for older GPUs, but it just isn't necessary for a modern GPU and CPU, they are vastly more power efficient these days.

Look here for a pretty good indication of what you'll need: https://outervision.com/power-supply-calculator.

I'd go with 850W. Gives you some overhead for future expansions and normal degradation over the lifespan of the PSU.
I have this one: https://www.evga.com/products/product.aspx?pn=220-G3-0850-X1

Wonderful and silent PSU.

1 hour ago, fwerff said:

I'd go with 850W. Gives you some overhead for future expansions and normal degradation over the lifespan of the PSU.
I have this one: https://www.evga.com/products/product.aspx?pn=220-G3-0850-X1

Wonderful and silent PSU.

+1

If your budget isn't tight then I'd go for the 850. It's there just in case and it'll give you room for more consuming upgrades if you ever decide to. 

Clay

Another recommendation for EVGA. Great PSUs with high quality components and a 10-year warranty on many of the models.

7 hours ago, vortex681 said:

Look here for a pretty good indication of what you'll need: https://outervision.com/power-supply-calculator.

Thanks , that's one of the calculators I used toi estimate the wattage. I think they tend to overestimate somewhat.

4 hours ago, fwerff said:

I'd go with 850W. Gives you some overhead for future expansions and normal degradation over the lifespan of the PSU.

The only circumstance that I would consider SLI in the future is if VR headsests directly benefitted.

In my current system i have a corsair TX850, it's about 5yrs old now! Is it worth buying a new PSU if I already have that?

On 1-12-2017 at 7:16 PM, Djang0 said:

In my current system i have a corsair TX850, it's about 5yrs old now! Is it worth buying a new PSU if I already have that?

I'd think a 5 year old PSU still has some time left, unless you never switched of your pc in that period.

When I bought the components for my new rig -this fall- I choose to renew my PSU because it was 8 years old.