Basic questions to get started with RTX / NVLink

[Streetwise]

I have some newbie questions about GPU as I'm about to dive it with a new system. A few questions in no particular order:

- Could a single RTX30XX do it all, or do I need two cards so I can keep working while a render is in process?
- If two cards are needed, is there any benefit to purchasing a high-end card for the secondary OS (Work) card?
- If I got two RTX3090 cards NVLinked, can I render AND work at the same time?
- The system I'm looking at can hold up to 4 RTX3080 cards. Since NVLink does not work with those, is it possible to send jobs to each card individually? Or would 4 cards be a waste?
- Do simulations work with GPU? Pheonix, tyFlow? As good as high GHz CPU?

I'm sure I'll have more questions... Just trying to understand how it all works before I purchase.

Thanks!

[Morne]

Besides a different workflow and various textures not being compatible, the number 1 issue is VRAM. No point in 8 X 3080 cards if your typical scene Maxes out the ram at 10GB

[Micha]

Interesting questions. I'm curious for the answers. Some thoughts:
* I would look for RTX3080 20GB, VRAM is important
* NVLink cost render power, so I wouldn't use it for all days
* the power supply needs to have enough cables for 4 cards


My current power supply has enough cables for 3 power cards only. I think about to buy a simple card without extra cables for OS display. Maybe someone has a good idea, which could be a good card. I use a 4k display.