Just catching up. Are you shooting N-RAW or ProRes? Be careful to check minimum sustained write speeds specifically. I'd suggest:

• Wise Advanced 640GB CFexpress Type B PRO
• It maintains 1400MB/s sustained write.

Re: "TIL! Thanks for sharing" - same here honestly. I've been doing a ton of reading because I'm still kinda new to this Z9 workflow and the thought of a card failing during a ceremony makes me sweat. I agree with the Wise suggestion but my bank account was already hurting after buying the camera body. I found a slightly cheaper path that worked for me during a long test shoot last week. I was really worried about the overheating stuff too...

• Make sure to check the sustained write speed specifically, not just the "max" speed on the box.
• I would suggest looking at the Angelbird AV PRO CFexpress B MK2 660GB. It is usually way cheaper than the Cobalt cards but handles the high bitrates really well.
• Also Lexar Professional CFexpress Type B Gold Series 512GB is decent if you can find a bundle deal, though it's a bit of a polarizing choice for some. Just be careful with the cheaper Silver series Lexar cards tho, I tried an older one I had lying around and it lasted maybe 3 minutes before the camera gave me a "card hot" warning and stopped. Tbh I'd rather spend a tiny bit more on a proven mid-range card than risk missing the vows.

• Grab Delkin Devices BLACK CFexpress Type B 512GB
• Be careful with slower cards, 8K 60p needs that 1500MB/s sustained write speed or itll probably crash mid-vow

TIL! Thanks for sharing

^ This. Also, I totally get the nerves... I was in the same boat last summer shooting a marathon event in 90-degree weather. I was so stressed about the heat and data rates for 8k, but honestly, I've been super satisfied with how everything handled it. No complaints at all once I stopped overthinking it and just looked at the actual test data.

• check the spreadsheets over on the nikon reddit
• look up those speed test videos on youtube
• the official nikon site actually has a compatibility list too Tbh theres a really solid video that compares all the top brands side-by-side specifically for the Z9. Just search for z9 cfexpress speed test on youtube and it's like the first result. It saved me so much time and actually shows which brands are just hype versus which ones actually stay cool and keep up with the buffer.