edstewbob
Well-Known Member
Both internal storage and microSD cards use flash memory but access to internal storage is much faster than a microSD card. MicroSD cards are rated at up to 10 MB/s write speed for the fastest ones, with my DX containing a class 4 card that has a 4 MB/s write speed.
Internal storage used with the TI OMAP 4460 uses an eMMC interface (V 4.41) with a maximum rated speed of up to 104 MB/s.
Due to the technical nature of flash memory writes always take longer than reads, sometimes much longer, and for microSD cards reads are rated as 8 times as fast as writes.
I could not find any reliable benchmarks for eMMC flash memory access performance but based upon the known speed of microSD cards and the potential speed of eMMC memory found on the SGN the speed of all flash memory operations will likely be much faster than would be possible if a microSD card were present.
I suspect or guess that the speed of the internal memory on the SGN is one of the reasons we see zero lag when taking pictures since the pictures must be quickly offloaded to flash memory to keep up with rapid picture taking. I also suspect that the camera first writes to RAM and then copies to a file on internal storage after capture is completed although several images could be stored in RAM before copying to flash. Since there are dual processors both of these operations could occur simultaneously.
I'm not sure it could happen this fast if a slower microSD card were the storage destination for pictures like it is on my DX.
Internal storage used with the TI OMAP 4460 uses an eMMC interface (V 4.41) with a maximum rated speed of up to 104 MB/s.
Due to the technical nature of flash memory writes always take longer than reads, sometimes much longer, and for microSD cards reads are rated as 8 times as fast as writes.
I could not find any reliable benchmarks for eMMC flash memory access performance but based upon the known speed of microSD cards and the potential speed of eMMC memory found on the SGN the speed of all flash memory operations will likely be much faster than would be possible if a microSD card were present.
I suspect or guess that the speed of the internal memory on the SGN is one of the reasons we see zero lag when taking pictures since the pictures must be quickly offloaded to flash memory to keep up with rapid picture taking. I also suspect that the camera first writes to RAM and then copies to a file on internal storage after capture is completed although several images could be stored in RAM before copying to flash. Since there are dual processors both of these operations could occur simultaneously.
I'm not sure it could happen this fast if a slower microSD card were the storage destination for pictures like it is on my DX.
