Re: Pi5 M.2 HAT

Pancho <Pancho.Jones@proton.me> wrote:

On 10/30/24 08:50, Andy Burns wrote:

Pancho wrote:
 

The official NVMe Pi Hat has been out for months,

 
Oh, I don't have a Pi5, and though I kept hearing about 3rd party NVMe
HATs and lack of official one
 

 
OK, I see there is a story about rPi launching actual NVMe M.2 SSDs. As
opposed to a hat. I've no idea why they would do that. The obvious
suspicion is cashing in on a brand name.
 
<https://www.techpowerup.com/328021/raspberry-pi-launches-nvme-m-2-ssds-and-ready-to-use-ssd-kits>

It may be they are doing it because supply of small-capacity 2230 NVMe is a
bit of a minefield.  eg I checked scan.co.uk and the smallest 2230 they have
is 512GB.  There are some 256GB sold by Amazon.co.uk which are more
expensive (and a few more dispatched by other sellers, of variable
trustworthiness).  At least with the RPi brand you know they're compatible,
and they seem to be decent value.

It's hard to know what is going on with the Raspberry Pi guys, the
RK3588 devices are clearly faster, lower energy, albeit with shit
software support. Who knows what will happen with the next generation
Arm SoCs. I guess maybe Raspberry Pi have a clue, and hence decided to
monetise the brand now, before a new product wipes the floor with them.

It'll depend on what fab slots they can get.  Not everyone can fab on the
latest process, especially with a budget.  Also how much cache they can
afford to put on the die.

RK3588: (64+64+512)*4+(32+32+128)*4+3072 = 6400KiB
RPi5  : 512*4+2048 = 4096KiB

RK3588 also has 4 extra A55 cores which RPi doesn't have, but is more
expensive ($100+ for the Banana Pi).

I guess I should get one, or maybe an alternative. I just bought a
NVMe USB enclosure which has appalling performance

 
Anyway, is it likely the write speeds are faster than the  read speeds?
I know some enterprise SSDs come in "read mostly" or "write mostly"
flavours, but for a Pi?

Dunno, IOPS doesn't mean a lot to me. As TNP says, maybe a write
operation is to cache, and a read is from main memory.
 
On many solid state persistence devices you see a very fast initial
write (presumably to cache) before quickly settling down to a much lower
rate for big files.

Any decent benchmarking tool should get past the cache to exercise the real
storage.

I think they've got them around the wrong way.  Their ODM Biwin's 2230 has
more read than write IOPS:
https://droix.co.uk/product/biwin-2230/

Theo