7 ms·
Personally I wish they'd add an m2 slot and scrap the SD card. It really is the bottleneck of the whole system. But they walk a fine balance with PCB space, b
by m-p-3 6y ago
Personally I wish they'd add an m2 slot and scrap the SD card.
It really is the bottleneck of the whole system.
But they walk a fine balance with PCB space, backward compatibility, performance, cost and user-friendliness.
- ed25519FUUU 6y agom.2 slot is definitely the best long term issue for keeping costs down but providing a way for high speed. Now that they’ve switched to USB, I don’t see power draw as an issue any longer.
- tachyonbeam 6y agoIt depends what you want to do with it. If you want to use it for a mobile robot, run the Raspberry Pi off a battery, then yes, power does matter.
- arcticbull 6y agoI suspect the power draw of a mobile robot would be dominated by the motors, would it not?
- tachyonbeam 6y agoThe motors aren't necessarily constantly on, and you don't need very big motors for a small robot.
- Teknoman117 6y agoThe speed would be much better than an SD card, but nowhere near the peak M.2 performance we've come to love. The SoC they use only has a single lane of PCIe Gen 2. So 500 MB/s peak (MB, not MiB) with large transfers. Throw in a PCIe switch or something so you can still attach a USB 3 controller and now you've doubled the price and power consumption.
- m-p-3 6y agoIf they add a m.2 slot now, at least it's already there for the next revision which they could improve the PCIe lane. And hopefully that would ensure the new form factor to be somewhat stable for a while after that.
- smileybarry 6y agoThey could add a SATA M.2 slot, then it's equivalent to using a 2.5" SATA SSD but in a neater form factor.
- TheRealPomax 6y ago500MBPS is already 1.5x SSD speed, so... I'd take it over SD any day of the week! Especially since at those speeds, you can buy just any random cheap m.2 and come out well on top.
- arcticbull 6y agoWhat's really hindering responsiveness and day-to-day performance isn't going to be sequential read and write speeds but rather 4K random IOPS. SD cards are not all designed or optimized around small, random reads and writes - the typical workload of a boot drive - and latencies can be staggering. Similar for USB sticks. On the other hand, these days the overwhelming majority of M.2 SSDs are at least somewhat optimized for 4K IOPS. The latest Sabrent Rocket M2 SSDs get some 650,000 4K IOPS vs eMMC at ~13000 (the Rocket is 50X faster) an SD card around ~2000 (the Rocket is 325X faster). Frankly if you stuck a Sabrent Rocket on a PCIe 1.0 x1 connector the performance would absolute savage an SD or eMMC solution on this workload. Even if they somehow also had identical sequential I/O specs.
- bufferoverflow 6y ago500 MB/s is more than enough for most applications.
- stjohnswarts 6y agoAck, why do away with SD slot? Sure add an nvme port that would be awesome but don't take away stuff, that's why we lost aux out on phones!
- sagarm 6y agoUSB SD card readers are cheap, if you need one. Many hubs have one built in anyway.
- TheRealPomax 6y agoSD card reading on the chip is also cheap, and doesn't require removing if you add an m.2 connector. No need to get rid of SD.
- freeone3000 6y agoIt might require removing to save on the physical space - an m2 connector requires a large amount of physical space compared to the SD card (for the retention screw). It might not have room for both.
- TheRealPomax 6y agoSo... that's fine, then? Telling people "you get an SD card connector and an m.2, you can't use both at the same time" seems perfectly reasonable to me. Have them overlap, done. Now people who want to use a $5 SD card with the slow speeds that come with that can do so, and people who want high speed but with the higher cost of a reliable m.2 drive instead can do so, too. No one loses.
- znpy 6y agoyes but an sd card can be bought for less than 10 $/€, whereas an nvme disk would cost about the same price of the whole rpi. you have to keep in mind the original goal of the raspberry pi project. if you want nice performance and low power consumption, you're better off considering a cheap intel nuc.
- m-p-3 6y agoLast time I checked, a NUC was considerably more expensive..
- bufferoverflow 6y agoSSD: $20 for 128GB on Amazon SD card: $15.20 for 128GB on Amazon The price difference is minimal. But the SSD is much much faster in that price range.
- Flibble21 6y agoYou're missing one of the very important aspects of a RPI is that it's cheap and accessible. Many countries around the world, particularly the poorer ones, don't have Amazon or ready cheap access to SSDs. What they do have access to is phone micro SD cards in adaptors. An 8 or 16GB card is plenty for a computer lab and is affordable and accessible.
- bufferoverflow 6y agoWhich country doesn't have access to SSDs?
- culopatin 6y agoThey are saying that having an SD port allows people to spend less by using 8-16gb storage cards that are much cheaper than a 128gb M2 SSD. In many countries the RPi is already a big expense on itself and import taxes and low demand often inflate its price even higher. Same happens to other electronics, combined with the reduce buying power, it all adds up really quick.