3080 + 1070ti= 20gbs vram but x8pcie speed worth it?

[vWORMHAT]

I have a 5900x, just upgraded to a 3080 and now I need to upgrade the psu from 650w to either 850w or 1000w. If I get 1000w then I could put the 1070 ti in there. And maybe get a nvlink (needed so blemder could use all 20gbs of vram right?) But this means the 3080 would run at x8.

 

I know the 1070ti wouldn't speed things up that much but the vram would be very helpful for my complex scenes.

 

1000w psu is around $50 more than the 850w, and an nvlink is around around $120

So if the nvlink is needed that would be $170 in order to use the 1070 ti in the PC is it even worth it considering the price?

 

So 1070ti + 3080  at x8 pcie speeds for blender yay or nay?

 

Is an nvlink bridge needed to access the vram in the 1070? 

 

 

[Zando_]

You can't NVLink GPUs that are not the same (or at least from the same series). GeForce cards do not do full NVLink, only Quadro cards with the connector do. GeForce cards just use the NVLink connector for higher bandwidth SLI, and again you need duplicate cards. 

[igormp]

1 minute ago, vWORMHAT said:

If I get 1000w then I could put the 1070 ti in there. And maybe get a nvlink (needed so blemder could use all 20gbs of vram right?)

The 1070ti doesn't support nvlink, but rather the regular SLI which is deprecated. Also, no, the memory won't be combined like that.

 

With that said, using more than 1 GPU will allow blender to split the job between both, so you could give it a try.

The drop in bandwidth should affect performance that much, maybe a 10% penalty or so.

[jones177]

Only 3090s and 3090 tis have nvlink.

My 3080 tis don't have it.

[vWORMHAT]

17 minutes ago, igormp said:

The 1070ti doesn't support nvlink, but rather the regular SLI which is deprecated. Also, no, the memory won't be combined like that.

 

With that said, using more than 1 GPU will allow blender to split the job between both, so you could give it a try.

The drop in bandwidth should affect performance that much, maybe a 10% penalty or so.

Does this mean. Of I had a scene taking up 10gb vram than I would most likely get an error since the 1070ti only has 8gb vram. Instead of pooling the memory it would just copy it to both?

[jaslion]

29 minutes ago, vWORMHAT said:

Does this mean. Of I had a scene taking up 10gb vram than I would most likely get an error since the 1070ti only has 8gb vram. Instead of pooling the memory it would just copy it to both?

No the gpu's will be treated as their own entity.

[Electronics Wizardy]

39 minutes ago, vWORMHAT said:

Does this mean. Of I had a scene taking up 10gb vram than I would most likely get an error since the 1070ti only has 8gb vram. Instead of pooling the memory it would just copy it to both?

If your rendering with multiple gpus, you max vram is the vram of the card with the lowest vram, not the total. The 1070ti might bake rendering a bit faster(probably not worth it though), but limit your vram use to 8gb.

[vWORMHAT]

Thanks everyone for the replies!