OK so something I am wondering having bought a couple of new CF cards for my Canon 5Dmk4.

I change the cards periodically as a wedding photographer just for safety of knowing they are not so old, the card I have just changed is a Compact Flash 64GB sandisk Extreme 120mb/s and I changed it for an identical card , both cards are genuine and verified by sandisk as I always get a check from them as a precaution and the older card is coming up to 2 years.

I did a read / write speed test between the new and old cards and there seems to be a difference of around 20-30 mbs especially on the read side between the old and new card ( the newer one reading around 80-90 mbs consistently. The same lexar pro CFR1 reader was used for both cards and test repeated a few times with the same results.

So my question is after many uses does the CF card read/write speed actually reduce with age ?

Thanks in advance

Wedding Photographer North East & Yorkshire Northumberland & Wedding Photographer Cumbria
 
Mar 25, 2011
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I think its more likely that new cards are faster. As new memory manufacturing comes online, the proportion of fast memory chips is likely to rise. As I understand it, memory of the same type is sorted by speed into different grades. Its likely that memory that exceeds the requirements for the rated speed is going into your newer CF memory. Typically, memory cards are a little slower than their rated speed when used in real world equipment, so faster memory may move it closer to rated speed.
 
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I think its more likely that new cards are faster. As new memory manufacturing comes online, the proportion of fast memory chips is likely to rise. As I understand it, memory of the same type is sorted by speed into different grades. Its likely that memory that exceeds the requirements for the rated speed is going into your newer CF memory. Typically, memory cards are a little slower than their rated speed when used in real world equipment, so faster memory may move it closer to rated speed.

that makes sense thank you :)
 
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Apr 21, 2015
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Solid state memory has to be written in blocks. If it's become fragmented, it may have to re-write whole blocks to fill partial ones slowing writes down to those blocks. That can slow things a fair bit on writes, but ought to be really minimal for reads. A high level format will make sure all of that is reset.
For read tests, you'd need to format both cards then test with the exact same files and do more than one test. Your operating system may cache files so that repeated copies from even the same card are different, so watch out for that...
Also you may have different internal chips. (hopefully the slow one meets spec and the newer exceeds it) They'd be the same now as new though...
 
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