CFexpress card runs HOT...like REALLY REALLY hot that you can't even hold it hot

L_Speed87 wrote:

RDM5546 wrote:

L_Speed87 wrote:

Not a huge issue in and of itself. Nand memory actually prefers to run hot, it works better when it does. Operating Temps of 70C are normal, which is pretty darn hot to the touch.

Even though a water temperature of 110° F (43C) is 'relatively-safe', exposure can be painful; the human pain threshold is around 106-108° F (42C) ... A child can suffer a third-degree burn in 124°F (51C) water in less than three minutes. Children and adults can be burned this badly in two seconds or sooner in 149°F water .. A safer temperature for domestic hot water is below 50°C. This is because water at a lower temperature takes longer to cause injury. For example: At 60°C, it takes one second for hot water to cause third-degree burns.

Exactly. Which is why i pointed out it's hot to the touch, but it's not really an issue from an operational standpoint. Many people assume that because it's that hot to the touch, something may be wrong or that it's going to die a quick death. I was pointing out that this isn't an issue as operationally, NAND memory has no issue running at that temp, it's part and parcel with the fast speeds you're going to get.

Whether your fingers enjoy touching it after a long transfer is a totally different issue entirely. One might want to wait a bit under such scenarios

The memory in the CFE and all flash cars is non volatile and by design relies on providing the semiconductor charge high enough energy to cross a charge high barrier to get into an isolated trap state in a controlling part of the storage bit cell. Going over this potential means it has to be supplied a significant power and the barrier has to high to prevent the charge dissapating from normal thermal energencies experienced.

So yes I agree the temperatures experienced in the hot CFE cards is normal and well within design tolerances. The card are within their thermal design envelopment for data retention but hot enough to potential cause burns during extended exposure particularly by children if held above 51 C for three minutes which is not likely because is quite unpleasant. It is also not likely because Canon this and it is part of their thermal management system to prevent burns that would result from a 60 C card. It is easy to see some difficulty the management system has keep humans, data collection, and camera components safe and in regimes of reliable operation for a 20 year product lifetime with zero regular maintenance.

So there is a distributed set of key locations the Canon software attempt to manage the temperatures of and I know of at least four and likely five serious hot spots that must occurs in some modes of camera operation. They do this with a temperature estimation thermal model and apparently three thermeter measure points. Not every danger has a direct thermal sensor and some of the areas are too small varied to put a temperature in. Particularly modeling the cool down operations is highly tricky as it requires data from all of the external case heatflow location of which there may be many and varied in locations. Knowing your sensors are cool is far from know all the sensitive components in the system are cool. Time is a factor there and fewer points are required if more time for reaching cooled equilibrium is allowed for.

We do not know know if all flash cards from different suppliers are exactly the same in their thermal ramp streaming write heating cycles. It is possible there are differences that may be only small from a perspective of camera writing time but this depends on the specifics of the cards and management firmware operation in the camera as well.

I own Sony and Lexar CF cards. Also Sony, Lexar and Prograde V90 SD cards. I do not have my R5 yet but I am now curious how long each will run under controled environmental experiments writing the highest speed video rates shown in the manual  within card specification for each card to observe the recording times vs manufacturer.