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p.1 #1 · p.1 #1 · A Technical Look at CF Express Power Consumption and Why the Sony Alpha 1 May Be a Power Miracle | |
A Technical Look at CF Express Power Consumption and Why the Sony Alpha 1 May Be a Power Miracle
Someone said I complained too much so I decided to do some technical research into CF Express vs UHS-ii SD card power consumption to understand why Sony made the choice of CF Express Type A + UHS-ii SD cards it did for the Alpha 1. Now that I have a deeper understanding of the magnitude of CF Express Type B power consumption, I can understand why Sony made the choice of going with CF Express Type A instead of CF Express Type B. The Sony Alpha 1 may also be a power consumption miracle if the 4.6 watts operational in the Sony specifications website is true with a CF Express Type A card. (Hint: I'm APPRECIATING Sony here, not complaining)
First, how much power does a UHS-ii sd card use when writing data? This establishes a power consumption baseline that we will use to compare with CF Express. We want to know both the nominal power consumption in watts when writing out as well as the the power consumption in the idle/sleep states since these are the two power levels that define how much battery life we can get out of a camera battery.
From a Flash Memory Summit presentation, linked to below, on UHS-ii, we see on the "UHS-ii is saving energy" page that the UHS-ii sd card they measured uses an average of 0.79 watts when writing a multi gigabyte burst at 242 MB/s. The idle/sleep state power consumption is 0.2 mW (0.0002 W).
https://www.flashmemorysummit.com/English/Collaterals/Proceedings/2015/20150813_FL31_Pinto.pdf
For CF Express Type B cards that are used in Canon and Nikon cameras, I was able to find a spec sheet for Delkin and for ProGrade that lists power consumption numbers. These spec sheets are linked below. This is where things get interesting.
http://www.farnell.com/datasheets/2815914.pdf
https://progradedigital.com/wp-content/uploads/2019/03/ProGrade_DS_CFexpress_Final_E.pdf
On page 15 of the spec sheet for the Delkin CF Express Type B cards, we find Table 4-2 that lists the average power consumption for their 128GB, 256GB, and 512GB Type B cards that are rated for 1000 MB/sec write. These cards require an average of 1.8, 2.3, and 2.5 watts respectively for writing out. Right here, this means that using a higher capacity CF Express cards results in significantly higher power consumption and these are not small power numbers at all for a battery powered device!!!
The UHS-ii sd card earlier in this rant used only 0.79 watts. The Delkin CF Express Type B cards use 2.27 - 3.16x as much power writing out compared to UHS-ii! This is an enormous difference for a battery powered device.
On page 16 of the Delkin spec sheet, we find it lists two sleep states for its CF Express Type B cards, PS3 at 30 mW and PS4 at 2 mW. Notice that even just idling or sleeping, these CF Express cards use an order of magnitude or more in power compared to the 0.2 mW of a UHS-ii sd card we showed earlier!!! No wonder battery life suffers when using CF Express cards, they are indeed power hogs compared to UHS-ii.
Things get even more interesting when we look at the ProGrade CF Express Type B spec sheet linked to above for their Gold and Cobalt cards ranging from 120 GB to 1 TB capacities. In it, we find it states a PS4 sleep power of 2 mW, same as the Delkin. Then, we also see it list the nominal 3.3 V of a Type B card and it shows a normal operating current of 1550 mA and a max of 2500 mA. This means a ProGrade Type B card uses 5.12 watts normally and up to 8.25 watts max! Those are enormous power consumption numbers for a camera and much worse than the Delkin let alone what UHS-ii uses!!! The ProGrade cards use 6.5x as much power as a UHS-ii card in operation!!! Now imagine if you were to use dual CF Express Type B slots, the power consumption gets unwieldy.
And with the burst shooting speed we expect out of our modern cameras, I surmise that the CF Express memory cards don't get much chance to go into the sleep states but rather stay in their average power consumption states in the 1.8, 2.3, 2.5, 5.12 watt, etc ranges we showed above. And from the Delkin spec sheet, we also see the power consumption when reading the CF Express card is significantly higher than the write power! It shows that read power is 20-40% higher than the already enormous write powers! That is just not acceptable.
This explains why everyone says CF Express cards are very hot when they pop them out of the Canon R5 or their card reader hooked up to their computer. These whole digit watt power numbers are enormous for a memory card. It also explains why there is such a heat issue and low battery life on the Canon R5. A CF Express card can easily use a majority of the power of the camera. It also goes a way to explain why the mechanical shutter on the R5 can't do high fps as the battery drains. It's because Canon needs to reserve a large portion of the power available for the CF Express and doesn't have much headroom. There is no way Canon could have put two CF Express Type B slots on the R5 with the battery it has and why only the 1DXiii has two (because of the enormous 1DXiii body). This extremely high power consumption by Type B cards could also explain some of the random camera freezing Canon R5 users are seeing that require a hard reset, the peak power consumption of some Type B cards are simply too high for the battery when doing bursts.
So why did I say the Sony Alpha 1 may be a power consumption miracle in the title of this thread? It's because there are TWO CF Express Type A slots on the Alpha 1 and the Sony site claims a nominal power usage of only 4.6 watts for the whole camera when it is taking a photo! Whether Sony measured this power number using the CF Express Type A slots or the UHS-ii slots on the Alpha 1 is unclear. I am hoping this number is done with the CF Express Type A slot because that would make the Alpha 1 an extremely power efficient camera and using the UHS-ii slots would greatly extend the already class leading mirrorless battery life. Maybe I won't need all 8 of the Sony FZ100 batteries I thought I would need for all day sports shooting after Sony disabled 3rd party FZ100 batteries on the Alpha 1. Maybe I can use the UHS-ii slots to save battery life.
This also goes to explain why Sony chose the CF Express Type A slot instead of Type B. The Type A cards only use 1 PCIe 3.0 data lane whereas the Type B uses 2 PCIe 3.0 lanes. This means the Type A cards can use a fraction of the power of the Type B cards since there is less circuitry to power in the cards. Sony doesn't list power numbers for it's Type A cards like Delkin and ProGrade does but I am very interested to see if anyone can pull these Sony numbers from somewhere.
https://www.sony.com/electronics/interchangeable-lens-cameras/ilce-1/specifications
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Feb 01, 2021 at 04:11 AM |
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