Seconding the recommendation above! Honestly, I've had issues with cheaper cards in the past so I'm cautious now. If ur looking for something solid within budget, check out ProGrade Digital 512GB CFexpress Type B Cobalt or the Wise Advanced 640GB CFexpress Type B PRO. Both are VPG-400, which is basically mandatory if u dont want 8K RAW to fail. I mean, spending $400+ sucks but it's safer than losing footage... gl! 👍

Oh man, congrats on the pre-order! I remember when I first jumped from SD cards to CFexpress for my R5, it basically felt like moving from a moped to a Ferrari lol. In my experience, the EOS R5 Mark II is a total beast, but itll literally choke if you dont give it the right fuel. Over the years, I've tried many different brands, and I've learned the hard way that "peak speed" is mostly just marketing fluff. What you actually need is sustained write speed, especially for that 8K 60p RAW.

For your situation, I would suggest looking at the ProGrade Digital 1TB CFexpress Type B Gold (Memory Card). I've been using their Gold series for a while now and they're solid workhorses. But honestly, if you're seriously worried about heat during long birding bursts or 8K sessions, you gotta look at the Delkin Devices 650GB BLACK CFexpress Type B Memory Card. It is VPG-400 certified, which means it wont drop below 400MB/s no matter what. I've pushed mine through 30fps bursts and it just doesnt quit, plus they have that insane lifetime warranty where they'll replace it in 48 hours if it bricks.

Another great mid-range option that fits ur budget is the Lexar 1TB Professional CFexpress Type B Card SILVER Series. It's a bit cheaper but still handles the R5 II high bitrates pretty well iirc. Basically, just stay away from the super cheap no-name brands on Amazon. They run SO hot and you'll end up with that dreaded overheat icon mid-shoot. Tbh, stick with Delkin BLACK or ProGrade Cobalt/Gold if you want total peace of mind. gl with the new rig!

TL;DR: Go for Delkin Devices 650GB BLACK CFexpress Type B Memory Card for the best thermal performance and VPG-400 reliability, or ProGrade Digital 1TB CFexpress Type B Gold (Memory Card) for a better price-to-capacity ratio.

Just saw this thread and honestly, I went through this exact same headache last year when I was prepping for a big wildlife trip. So, basically, most people just look at the big "up to 1700MB/s" numbers on the box, but for a beast like the R5 II, those peak speeds are almost meaningless. You gotta look at sustained write performance. If a card drops below its minimum speed while youre mid-burst or shooting 8K 60p, the camera is gonna throw a fit and stop recording. It's literally the worst feeling when you miss a shot cuz of a "Slow Card" error.

Story time: I remember being out at a local marsh with some cheaper cards I thought would be "good enough." I was tracking a kingfisher, hit the burst, and halfway through... the buffer just choked. I realized then that the R5 series is super picky about heat management too. Some cards get so hot they actually trigger the cameras thermal shutdown earlier than others. I ended up looking into brands like Angelbird or Wise because they tend to focus more on that stable, sustained throughput rather than just flashy marketing numbers.

Before you drop $500 tho, I gotta ask—how much 8K RAW are you actually planning to shoot daily? Also, do you already have a high-speed USB 3.2 Gen 2x2 reader? Ngl, a slow reader makes the whole workflow feel like a crawl even with a 1TB card. It definately pays to think about the whole chain, not just the card itself. Good luck with the new body, youre gonna love it!

Solid advice 👍

Like someone mentioned, the sustained speeds are really the only thing that actually matters for that 8K stuff. I've been shooting with high-end mirrorless bodies for a long time now and honestly, you gotta be so careful with the heat. I've had a few close calls where I almost lost a whole afternoon of wildlife shots because the buffer just wouldn't clear... it's super stressful when your gear starts lagging. Before you drop $500 on a card, I would suggest doing a bit of homework:

• search youtube for r5ii thermal stress tests to see which cards actually stay cool
• check the latest reddit threads for real-world 8k raw benchmarks from actual owners
• look up the specs for the Sony TOUGH CFexpress Type B 512GB or maybe the Angelbird AV PRO CFexpress B SE 1TB I'm pretty sure there's a killer comparison video that just came out that covers all the thermal issues, if you search for r5 mark ii card speeds it should be right at the top. Definitely be cautious and do a bit of digging first though... you don't want to find out a card is slow while you're actually out in the field. Good luck with the Canon EOS R5 Mark II, it's a total dream to shoot with!

Ugh, honestly the stress of picking the wrong card is so real. I've been shooting for a long time and it still feels like a total gamble every time a new body drops. It is so frustrating that we have to worry about compatibility issues or the camera just stopping mid-shoot because the card isnt certified enough... basically feels like a tax on top of the camera price. The good news is I've been pretty satisfied with a few specific ones lately:

• Angelbird AV PRO CFexpress B SE 512GB is super reliable and hasn't given me any heat warnings yet.
• SanDisk Extreme PRO CFexpress Type B 512GB is a classic choice and honestly works well enough for most bursts.
• OWC Atlas Ultra CFexpress Type B 650GB is what I grab for the heavy 8K stuff since it handles sustained writes like a champ. Glad I am not the only one annoyed by the card hunt... it's a headache but these have kept me happy so far.

Ok so, i get the hype but honestly... dont just throw money at the flashiest specs. Since youre on a budget, you gotta be careful cuz some high-end cards are overkill while cheap ones might actually fry your buffer or overheat the camera.

For your situation, here's what I recommend looking at to save some cash without sacrificing safety:

- Lexar Professional CFexpress Type B Card DIAMOND Series 512GB is a beast, but maybe check out the Lexar Professional CFexpress Type B Card GOLD Series 1TB (New Gen) instead. It's usually much cheaper and the newer version handles sustained writes way better than the old ones.
- If you wanna play it safe, I would suggest the Angelbird AV PRO CFexpress B SE 512GB. They're super reliable and usually priced around $160-$200, which is a steal for VPG-400 equivalent performance.
- Be careful with some older brands, but Sabrent Rocket CFX 1TB CFexpress Type B is highkey a great value play. I think they're around $300? Just make sure to double check firmware compatibility.

Honestly, 1TB is the sweet spot for 8K. Just dont forget a good reader or youll be waiting forever lol. 👍

Stumbled upon this while researching for my own pre-order! I'm still a bit of a beginner with these high-end bodies, but I've been diving deep into the technical side to make sure I don't waste money. One resource that’s been pretty much a lifesaver for me is the Camnostic website or Alik Griffin’s blog. They do these really detailed thermal and speed tests that go way beyond what the manufacturers put on the box. Tbh, seeing the actual charts for how hardware throttles after 20 minutes of 8K recording is a huge eye-opener. Quick tip: Look for cards that use the newer controller chips because they tend to run way cooler, which is basically the biggest hurdle for the R5 II. I’ve been eyeing the Angelbird AV PRO CFexpress B MK2 1TB because their sustained write specs are actually listed clearly on their data sheets, which is rare. Has anyone tried their stuff in the original R5? I’m pretty curious if they hold up over a year or two of heavy use without the speeds dropping off?? It’s a lot of money to drop if the performance degrades over time!

> I’m worried about hitting a wall during a long birding sequence or having the video recording cut out due to overheating or slow write speeds. My own journey with these high-res bodies basically taught me that the biggest danger isnt just a slow card, but an inconsistent one. I once lost a crucial sequence because my card couldnt handle the heat during an extended burst. The camera didnt just slow down; it basically froze as the buffer struggled to dump data into a card that was thermal throttling. You should be particularly cautious about cards that emphasize burst speed over sustained performance. In my experience, if the card isnt rated for high-bandwidth video, it likely wont survive the 45MP RAW bursts for long. Ive also run into issues where generic cards caused the camera body to get noticeably warmer than usual, which is the last thing you want during a long 8K session. A few things to keep in mind:

• Avoid cards that dont explicitly state their minimum sustained write speed.
• Be wary of deals that seem too good to be true, as counterfeits are a real issue.
• Older firmware on some cards can cause compatibility issues with newer Canon bodies. Its definitely worth spending the extra bit for peace of mind when youre shooting once-in-a-lifetime moments. Tbh, losing shots because of a storage bottleneck is the worst feeling.