3 ms·

What's the issue with a jump from 12w to 25w?

wtallis 3y ago
We're talking about an SSD form factor that's 22x80mm and is fed by a couple of card edge pins carrying 3.3V. 12W was already pushing it.
- formerly_proven 3y ago
  According to the one-page datasheet of a Foxconn M.2 M-key socket, maximum current per pin is 0.5 A (they're tiny, after all). Since M.2 M-key has a total of nine pins carrying 3.3 V this would limit power to 15 W before any heat dissipation considerations plus connector derating because the toasty SSD is heating the connector up.
  - deleted 3y ago
    [deleted]
- KennyBlanken 3y ago
  ...on a device that weighs about 10 grams with a heat capacity likely around 0.4J/gram-degrees-C. 10Ws for such a device if I did the math right is around a 2.5C/sec rise in device temperature.
ilyt 3y ago
The M.2 sockets on motherboards don't exactly have great cooling, and SSDs don't usually even come with radiator. The positioning can also be pretty iffy, mine have one next to CPU, another just under GPU (no chance getting fan there) and those are the "fast" (directly connected to CPU) ones! The another 2 slots are again under GPU (one filled with wifi/bt card), and only last 2 are far away from other hot components and get its own heatsink. but those are not directly connected to CPU
- kdmytro 3y ago
  I don't think this would be a factor. Some PCI-E 4.0 SSDs already come with metal heatsinks out of the box. If future SSDs needs addtitional cooling, this will be communicated to the buyer. I think that the bigger question is whether 25W can be phisically supplied to the drives by contemporary motherboards. What is the power limit for the m.2 ports?
  - ilyt 3y ago
    At least according to wikipedia each pin is rated up to 0.5A with I think nine 3.3v pins so technically just around ~15W peak Technically that's what U.2 (2.5 inch form factor for SSDs) would be for. They get 5V/12V and thicker connector, I severely doubt M.2 could swing 25W as it only has 3.3V on it

We're talking about an SSD form factor that's 22x80mm and is fed by a couple of card edge pins carrying 3.3V. 12W was already pushing it.

formerly_proven 3y ago
According to the one-page datasheet of a Foxconn M.2 M-key socket, maximum current per pin is 0.5 A (they're tiny, after all). Since M.2 M-key has a total of nine pins carrying 3.3 V this would limit power to 15 W before any heat dissipation considerations plus connector derating because the toasty SSD is heating the connector up.
- deleted 3y ago
  [deleted]
KennyBlanken 3y ago
...on a device that weighs about 10 grams with a heat capacity likely around 0.4J/gram-degrees-C. 10Ws for such a device if I did the math right is around a 2.5C/sec rise in device temperature.

ilyt 3y ago

The M.2 sockets on motherboards don't exactly have great cooling, and SSDs don't usually even come with radiator. The positioning can also be pretty iffy, mine have one next to CPU, another just under GPU (no chance getting fan there) and those are the "fast" (directly connected to CPU) ones! The another 2 slots are again under GPU (one filled with wifi/bt card), and only last 2 are far away from other hot components and get its own heatsink. but those are not directly connected to CPU

kdmytro 3y ago
I don't think this would be a factor. Some PCI-E 4.0 SSDs already come with metal heatsinks out of the box. If future SSDs needs addtitional cooling, this will be communicated to the buyer. I think that the bigger question is whether 25W can be phisically supplied to the drives by contemporary motherboards. What is the power limit for the m.2 ports?
- ilyt 3y ago
  At least according to wikipedia each pin is rated up to 0.5A with I think nine 3.3v pins so technically just around ~15W peak Technically that's what U.2 (2.5 inch form factor for SSDs) would be for. They get 5V/12V and thicker connector, I severely doubt M.2 could swing 25W as it only has 3.3V on it