graphics card - Running 3 ASUS ROG PG348Q with 2 Crossfired ASUS Vega 64

So, I'm putting together my wishlist for the coming year of components to build my next computer with. It's a rather John Hammond sort of endeavor, and so I am more then happy to put a lot of money into the system as I spend a lot of my free time gaming. As the title says, I found the ASUS ROG PG348Q 34" curved monitors and fell in love, they are gorgeous and what I want sitting on my desk with this new system. I had already found the Vega 64 video cards and had planned to crossfire them, but then something occurred to me as I was thinking about limiting factors.

The maximum resolution that the Vega 64 can render according to the stats on the manufacturer's site is 7680x4320. Which is very respectable, but the resolution on a single PG348Q monitor is 3440x1440. This is when I became rather concerned, and the question became apparent.

Would the Vega 64's being crossfired extend their maximum rendering capability, or would is merely spread the load of that 7680x4320 across the two video cards memory? I figured I would come ask people far more knowledgeable then myself about this topic before I start ordering parts only to find out they aren't going to perform as imagined.

Thank you for the time and I hope to hear back about this concern.

Answer

Would the Vega 64's being in a Crossfire configuration extend their maximum rendering capability, or would is merely spread the load of that 7680x4320 across the two video cards memory?

Crossfire works by taking two cards, separating the workload equally among them, to the software they appear as a single card. This is the reason you cannot use different GPUs that are different in Crossfire.

In general, both cards will render a frame in parallel, which is the reason Crossfire provides a performance boost. This also means the maximum amount of VRAM an application can use is the amount the smallest amount of VRAM a GPU has access too.

What this means is if you have a 2GB and 4GB GPU, both running the same GPU core, the total amount of VRAM your system can use is 2GB. This is obviously due to the fact if both cards are working in parallel, the workload between them must be equal.

If the maximum resolution a Vega 64 can support is 7680x4320, then the maximum resolution a system with two of them in Crossfire will be 7680x4320. The workload to support that resolution will just be shared equally among both cards.