What's better two 3090's or one 4090?

[earthworm_tim]

Hello

I am wondering whether to sell my current TUF 3090 to buy a 4090, or just to buy another 3090? I use it for rendering in redshift C4d.

I know I will probably want to upgrade again in future either way as the better the graphics cards the better, just not sure what's most cost effective thing to do..

My power supply is 1000watts

Thanks!

 

[Tetras]

I'm not sure we'll be able to answer that here.

This was the best I could find (benches) and the answer is: the 4090 is almost, but not quite faster than 2x 3090. In redshift's documentation they mention there are multiple render modes and APIs, which also influence how much performance you get, which I don't really understand well enough to comment on ("multiple gpu scaling", here).

 

[earthworm_tim]

No worries! That's a great help thank you

 

[Trickle]

The usual benefit for 2x 3090s, 48gb, doesn't seem to apply to C4D red unlike some other render engines.
The one other plus point I can think of is not having to deal with the 2nd hand market for your existing 3090.

 

[Chuk_Chuk]

The usual benefit for 2x 3090s, 48gb, doesn't seem to apply to C4D red unlike some other render engines.
The one other plus point I can think of is not having to deal with the 2nd hand market for your existing 3090.

This is not true. The documentation linked above states that vram is pooled together when using NVlink (which is what other render engines do).

@earthworm_tim If you feel like you can/do use more than 24GB of VRAM while rendering then two 3090s will be best (you will need a new PSU though). Otherwise the 4090 is the better option. In terms of cost efficiency, potentially a second hand 3090 plus a PSU will be cheaper than a 4090 in upfront cost.

 

[Trickle]

I found about 10 sources yesterday in the past year when I checked stating memory pooling doesnt work, but I didnt (and have no interest further in doing so) any official documentation - I don't use C4D any more. Would recommend OP do their own research here if thats of interest to them.

 

[newuser]

I looked at adding another 3090 with nvlink and I decided that finding a decent card the same as the one I have, finding a correct spec and length bridge, upgrading the PSU and dealing with two 3090s heat output in one case was more hassle than I was prepared to deal with.

I went the 4090 route and it's about 80% quicker than the 3090 for my uses although that's going to depend on renderer and job. It also uses about the same power as the 3090 did while rendering. Does reasonably well at gaming as well if you're so inclined.