Originally posted by Venom3300 7- the time it takes to play back an image and clear the buffer is entirely too long
Just a couple points that might help...
Instant review might be delayed a slight amount if you have in camera lens corrections enabled (distortion, vignetting, abberation, etc.). If you shoot RAW you can turn them off since they only affect the JPEG, and I believe it will still spend time processing the thumbnail JPEG it puts in each RAW file.
Make sure you have a fast SD card since even Class 10 cards can limit the camera. Sometimes you get a bad card, which can make it perform worse than it's rated. SD cards are also fastest when they're freshly formatted. Try formatting your card to see if that makes it a little faster. (*See note below)
The Sandisk Pro Extreme cards are great, though pricey. Some people have shown that the K-3 itself can't write faster than 40 MB/s, but a faster card can't hurt. I have a pair of
PNY Turbo 64GB microSD cards in my K-3 using microSD to SD adapters and I have no issue with buffer, though I don't shoot long bursts on continuous-high very often since continuous-low is enough for me. I can fly through images when I view them in playback though, so any lag you see there is probably card related.
*Flash memory doesn't get fragmented the same as hard disks, but when you write and delete files you end up with partially filled data blocks. Data blocks are read and written as whole blocks, so to add more data to a partially filled block the controller has to read out what's in the block already and re-write the whole block again with the new data added. Writing files to partially filled blocks require more blocks to be read/written than if writing to empty blocks, and empty blocks are written without reading first, which is why a freshly formatted empty card is faster.
This is also why SSD's lose performance over time, especially with random writes. Newer SSD's get around this by having a TRIM function that restores performance by merging partially filled blocks and freeing up full blocks for writing. (Similar to defragmenting, just on data blocks instead of files.)