Different classes of memory cards question

I have seen Class 4, Class 10, and others, but what does it mean? Is that build quality or something?

Also, for a 60D, what is the best memory card I can get for under 60 bucks? Best size/speed/durability. I want to get into shooting RAW format pictures with this camera since I mostly did JPG on the Xti due to space limitation on the card. My good card (extreme IV) was only a 2gb, and I hated using the 8gb because it was really slow (133x)

Also this brings up another question... what is the "x" for? I really only understand Mb/s... Why do we need to have an "x" speed as well, whatever "x" is.

Per Market Watch: http://www.buydig.com …uct.aspx?sku=SD​SDU064GA11 64GB SD card for $57. You'll probably never run out of space there.

Shutterwolf wrote in post #14388753
I have seen Class 4, Class 10, and others, but what does it mean? Is that build quality or something?

The 'Class' classification for SD cards refers to their minimum speed. So a Class 10 is guaranteed to do at least 10 MB/s. It's a bit of a stupid system, because Class 10 is the fastest, despite the fact that current SD cards are way faster than 10 MB/s.

Shutterwolf wrote in post #14388753
Also this brings up another question... what is the "x" for? I really only understand Mb/s... Why do we need to have an "x" speed as well, whatever "x" is.

The 'x' classification was brought in because marketing droids decided that users wouldn't be able to understand MB/s as a speed rating. (Note it's MB/s not Mb/s - the former is MegaBytes per second, the latter is Megabits per second; that's 8 times slower. Mb/s is commonly used when talking about data transfer rates, so it really is important to use the right one).

In the olden times CD writers could write at an incredible 150 kB/s. Then faster drives were introduced and the 'x' labelling started. 300 kB/s drives were 2x, 600 kB/s drives were 4x; etc., etc. And the same system started getting used for memory cards. So your 400x card will be able to do 60 MB/s.

hollis_f wrote in post #14391684
The 'Class' classification for SD cards refers to their minimum speed. So a Class 10 is guaranteed to do at least 10 MB/s. It's a bit of a stupid system, because Class 10 is the fastest, despite the fact that current SD cards are way faster than 10 MB/s.

The 'x' classification was brought in because marketing droids decided that users wouldn't be able to understand MB/s as a speed rating. (Note it's MB/s not Mb/s - the former is MegaBytes per second, the latter is Megabits per second; that's 8 times slower. Mb/s is commonly used when talking about data transfer rates, so it really is important to use the right one).

In the olden times CD writers could write at an incredible 150 kB/s. Then faster drives were introduced and the 'x' labelling started. 300 kB/s drives were 2x, 600 kB/s drives were 4x; etc., etc. And the same system started getting used for memory cards. So your 400x card will be able to do 60 MB/s.

Ahh ok cool, thanks for the info!

Actually, the "Class" system is supposed to represent the minimum sustained write speed under somewhat-standardized conditions. The "x" rating frequently reports the burst speed. And it's important to note that some vendors measure the burst rate under highly idealized conditions, and will quote the faster read speed just to get better sounding numbers.