idk about pushing those limits without proper precautions, so just make sure whatever you buy has a solid thermal rating. Delkin Devices Power V90 SDXC 128GB has been super reliable for me in the dual slots without getting dangerously hot during long takes. double-check your firmware updates too just in case...

^ This. Also, man I feel your pain so much on this because I was literally up until 3 AM last week trying to figure out the exact same thing for my own setup (and my brain was totally fried by the end of it). I'm no expert, but I ended up diving down a massive rabbit hole comparing a few different cards before finally pulling the trigger. Here is what I found out during my late-night research:

• OWC Atlas Pro V90 128GB: Super solid build quality and sustained write speeds, but runs slightly pricier per gigabyte.
• Silicon Power Superior Pro V90 128GB: Way cheaper upfront, though a few people mentioned varying batch reliability for marathon recording sessions. Anyway, whatever you end up grabbing just make sure you don't cheap out on the actual reader too — wait, no — I mean, just test it thoroughly before a real shoot!

To add to the point above: ngl, I see why people stress over V90 cards, but tbh you don't even need them unless you're shooting 6K raw. For standard 4K 60p, V60 cards handle the bitrate fine and run way cooler.

• Sony SF-M Tough Series UHS-II V60 256GB
• ProGrade Digital V60 256GB Idk if V90 is overkill for your workflow, but saving money on V60s is lowkey the better move.

Oh man, congrats on the S5II! You're gonna love it (seriously, the autofocus compared to older models is just night and day). I'm no expert by any means, but I literally just went through this exact same rabbit hole last week while setting mine up — my browser tabs were an absolute mess. Anyway, skip the SanDisk anxiety if you're worried about the heat. I ended up grabbing the Lexar Professional 2000x SDXC UHS-II V90 and it has been rock solid for the heavy 4K 60p stuff without getting sketchy or dropping frames. If you want to save a few bucks and don't need absolute top-tier burst speeds for photography, the ProGrade Digital V90 UHS-II is also super reliable and a bit cheaper. Just make sure whatever you pick is on Panasonic's approved media list so you don't run into random write errors halfway through a shoot!

Congrats on the new camera, but honestly you dont need to overspend on these crazy expensive cards. Dealer wanted $400 for name-brand stuff at the local shop, but I did it way cheaper. I run the Kingston Canvas React Plus V90 128GB and it has been bulletproof for heavy video, costing way less per gigabyte over its lifespan than the competition. If you want a cheaper backup, the Transcend SDXC UHS-II V90 64GB gets the job done for basic shoots without breaking the bank...

So funny you ask this — last summer I ran into the exact same overheating mess with long 4K 60p takes on a hot outdoor shoot. Before I suggest the exact setup that finally fixed my drop-frame issues, what is your typical recording length per clip? Are you mostly running continuous 30-minute takes, or shorter interview snippets? Quick checklist of what matters most for this body:

• Sustained write speed over peak burst
• Thermal dissipation in the dual slots
• Actual firmware version on your cards Let me know your average clip length and I'll drop the exact specs you need.

To add to the point above: yea sandisk is totally overrated for this body and way overpriced anyway. I switched to the ProGrade Digital V90 256GB after my lexar got warm and it runs super cool even during long 4K 60p takes. Grab that one and you wont have to stress at all.

So funny you ask this — last summer I spent three entire days staring at different memory card specs until my eyes literally felt like they were going to melt out of my head. It’s honestly such a headache trying to figure out which brand won't quit on you in the middle of a shoot — the anxiety of thinking you've lost an entire day's work is just the absolute worst feeling. I still get stressed thinking about that one time my card corrupted at a wedding, total nightmare. Anyway, I’m just catching up on this thread now, but honestly, you shouldn't stress too much about the specific brand. If you want the most accurate info, just do this:

• Search YouTube for 'Panasonic S5II card stress test' — there's a really good video where a guy runs every card through a gauntlet.
• Check the official Panasonic support page for their media compatibility list.
• Browse the Reddit r/Lumix archives. Just poke around those, it's way easier than agonizing over it yourself!

Saw this earlier but just now responding... man this comes up a lot.

• totally agree with the heat complaints, its honestly driving everyone nuts
• firmware updates wont even fix hardware cooking itself idk why people keep buying the exact same problematic models when half the forum is already burning through replacements...