Canon EOS Rebel T6 (1300D) Busy Signal, write speeds, etc.

I just upgraded from a first gen Canon EOS Rebel DSLR to a like new condition T6. I, and the folks at my local camera store, reasoned that anything I get would be a huge jump, and it MOSTLY is.

• When shooting RAW, I can only crank out 3-5 quick shots, either rapidly depressing the shutter, or in burst mode. I do understand it can only shoot 3 fps burst.  But, after that I get a Busy signal and it takes 1-3 seconds to clear. Upon clearing, I can shoot maybe 2 shots before it goes busy for 1-3 seconds again. This remains unless i stop and give the camera a rest.  I thought 3 fps was continuous.  NOT 3 fps then rest for up to 3 seconds.  
• When shooting RAW + L, the delays are the same to a little greater.
• When shooting full sized jpg's, the busy signal doesn't seem to show at all when just shooting indivual shots, and shows intermittently but clears almost immediately in burst mode. So, I can shoot in burst mode almost continuously, but only jpg's.
• I am experimenting between a Sandisk 64gb Extreme (10, U-3, 60mbps-write)  and Sandisk 64gb Extreme Pro, 10, U-3, 90 mbps write) cards.  

So far, I can only detect a slight difference in write speeds if any between the Extreme and the Extreme pro (60 vs 9 mbps write speeds), and I may be hallucinating.

I have played with fully Auto vs Manual, and adjusted shutter speeds and ISO based upon light and subject, and have seen no improvement in write speeds and no change in speeds shooting RAW, RAW + L, and Jpg as mentioned above.

Unless I am missing something, which I quite possibly could be, the biggest bottleneck seems to be the write capability and/or buffer size/speed of the camera itself, when shooting RAW or RAW + L.

Does anyone happen to know the actual buffer size and write speeds of the T6?

I got it in new condition with only 2336 clicks, for $224 plus a Tamron 18mm-270mm lens for $116.  With a trade in of an old lens i wasnt using, I paid $169 for the whole package, so I didn't leave any money on the table.  And it is a big jump from my 2002/2003 model.  But, I'm wondering if I can get more out of it, or if there are some tricks to working within the limitations.

Thanks!

I don't know the write speeds but you're going to be bottlenecked more by the capabilities of the camera ad card interface rather than your memory cards.

The t6 is the lowest-end model that Canon makes so there's bound to be a lot of compromises. It's a really good deal for what you paid for it though.

There's nothing you can do to improve the speeds, unfortunately . They're hardware limitations .

One thing that might help a little is turning off all optimizations.

I don't know what the t6 offers, but there's things like lens corrections, ALO (auto lighting optimization), and other features that will keep your camera busy processing. I don't know if it'll help to turn off noise reduction. On one end, your camera has to process noise reduction, on the other end, pictures with more noise take a little bit more storage, which is what you want to minimize.

For cameras with faster bursts, turning off all of these things can make a noticeable difference. It's worth giving it a shot.

And like you wrote, there's also jpeg. I'd stick with raw for that sensor though since it is quite noisy, but manageable at ISO1600. And yes, definite upgrade over the 6mp on the original rebel.