R5 Buffer Clearing

Started 2 months ago | Discussions thread
OP Tazz93 Senior Member • Posts: 2,620
Re: R5 Buffer Clearing

John Sheehy wrote:

Tazz93 wrote:

Steve W wrote:

Tazz93 wrote:

When I first got the camera I checked the buffer and it was able to clear the buffer from the CFexpress card in under 10 seconds (with the Sony Tough 128GB). Now with both of my cards (Sony Tough 128GB and Lexar 128GB), it takes the same time as the UHS-II cards, which is roughly 20 seconds. I can see why Canon might have throttled it down, but I'm curious if others are seeing the same performance drop.

Personally, I'm not sure if it just my camera or if one of the recent firmware updates have altered it.

Have you set up your R5 to write the same image to both card simultaneously? If so that is probably it because with will write the both at the same time a the speed of the slowest card. Also what is the guaranteed write speed of the UHS-II cared ( it is UHS-II I hope and a fast one) Can you provide more specific information on your UHS card?

That's with only one card in the camera, but very good idea. That easily could have been the issue. That said, don't get sidetracked on the SD card, it works wonderful, and 20 seconds to clear the buffer on an SD card is quite good.

The CFexpress cards should be around 6 second to clear. I think I might have been a little vague before, but the problem is with the two CFexpress cards. Neither is able to clear the buffer as quickly as before.

See the article below for reference on a speed test of the various cards.


Have you since changed to settings with smaller file sizes (RAW to JPEG, FULL to 1.6x, or RAW to cRAW)? Maybe there is overhead per file in clearing the buffer that goes beyond raw MB/s. I haven't done the math, so I am just guessing here.

I never shot anything other than RAW since I got the camera, and the original test of the buffer was in RAW. That also matched the test from the Peta Pixel article above. That said, I'm assuming the buffer is a set memory size. With that being the case, I'd think you will still save a set amount of data to the buffer and unloading it would be unaffected by file type as it will save that same overall buffer depth. So long story short, moving 5 GBs of data is still 5 GBs of data whether its RAW, CRAW, or JPEGs. I could be wrong but, I don't think it matters unless something is drawing additional CPU cycles.

Did you format the card in your computer or the camera? My CFExpress card came formatted, but lost files (they became 0 bytes) when they were being downloaded to the computer, until I low-level formatted it in the camera (which took no appreciable time at all for 128GB).

Yes, the cards have been formatted before each try. Both "Low" and normal level.

I also tested each card in my computer and both CFexpress cards move 820+ GBs/sec attached to a basic reader. Incidentally, the SD card that clears the buffer in the same time as the CFexpress cards only move 240GB/sec on the computer. I really think Canon throttled it back.

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Mike Jackson - Wildlife Photography Enthusiast

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