My experience with earlier models, FWIW, is that you don't actually need the latest high speed SD cards, because the OS has proper buffering.
Action cams (e.g. gopro) have primitive software with primitive buffering so need the absolute fastest and expensive SD cards, even just to shoot 4K at 30fps (100mbps). That is about 10mbytes/sec *average* data rate, which even the cheapest CD card can do.
So I think it won't be an issue. I don't know the bitrate of the 8K mode though. OTOH it doesn't stabilise in 4K or 8K... same as the S7 actually Good 4K needs 100mbps so good 8K should need 400mbps which I am sure the S20* won't be doing.
No, it does not support the read and write speed of UHS-ii. I am assuming it is UHS-i like all the other phones. I would worry more about the certifications at that point. The newer A2, U3, and maybe V30 certifications would be fine. I think the perfect price to performance would be the SanDisk Extreme. It ticks all the boxes and doesn't break the bank too much.
Edit... I know this because I asked their associates via chat. They checked their resources (I am assuming a spec sheet) and confirmed that it does not support the UHS-ii standard. Therefore, the assumption is that they will support the UHS-i standard.
thanks for replying guys, this is my chat with samsung today:
Samsung: Good morning, welcome to WhatsApp! Good question, It's a bit complicated but UHS II should be supported and also be a little better/faster. I'll try to confirm this with our specialist to be sure and I'll report back on it as quick as possible. ^Joey
Hi, It's clear to me now. You probably won't notice any difference in speed when using an UHS II card but this will be useful/necessary for 8K video recording. Do you have any other questions for me? ^Joey
so for max options is a UHS I, 10 class, U3, V30 OR UP TO V90 cards right ? does the V30 V90 make big difference ?
V30 through v90 are certifications that are meant for video recording. That's why he was saying it would benefit the 8k recording to have a higher UHS-ii card because they have higher video recording certifications that UHS-i doesn't or couldn't achieve. I don't think it's as big as a deal as the A2 certification if you are going to put apps on your SD card. This certification is for application use. It will speed up the little things it searches and queues for. The IOPs for smaller files are typically larger than ones without that certification is what I researched. If you are just using it for photots and video, then the v60 or v90 would be optimal for that 8k video storage.
You have to pay attention to which ones you are looking at. Sandisk is overlapping on some models that make it confusing. There is an Extreme Pro that is UHS-ii and UHS-i. One is v30 (UHS-i) the other isn't V rated (UHS-ii) but it says 300 MB/s read speed on it.