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Lightpeak vs. SSD

M

monaarts

macrumors 65816
Original poster
Jan 16, 2010
1,168
51
Kennesaw, GA
Hey guys,

I have a question about the whole Lightpeak thing... I have a 2010 13" Macbook air, which gets speeds around 190MB/s write and 210MB/s read. The lightpeak gets about 10GB/s read and write simultaneously, which converts to about 1280MB/s. What benefit would lightpeak be if it can't go any faster than the ssd? Just curious. Thanks!


- Joe
 
Hi there,

Light Peak is meant to serve up a pipeline for external IO (like a USB port for example), except that Light Peak isn't USB.

So for example, if Apple built a Cinema Display that is Light Peak capable, then it could serve up display audio and maybe even USB over that connection right to the MacBook over a single connection. It's meant to be fast, and consolidate how many ports you see external to the laptop.

I'm just giving you an example. I'm not really sure what Apple's plans around this interface might be!
 
You can connect a display though lightpeak. GPU's take up a huge amount of bandwidth. Also, lightpeak has the potential for massive amounts of daisychaining, letting the user have less ports on a computer, with the same amount of functionality.
 
Okay... I suppose that makes sense. I just picture people wanting to use such a fast speed for an external HDD, which is MUCH slower than what lightpeak offers, as I mentioned before.
 
one more thing... rumors say that the iPad might have a lightpeak port... What benefit would that have then? Because the SSD in it isnt going to be any faster than in my MBA.



- Joe
 
monaarts said:
I have a 2010 13" Macbook air, which gets speeds around 190MB/s write and 210MB/s read. The lightpeak gets about 10GB/s read and write simultaneously, which converts to about 1280MB/s. What benefit would lightpeak be if it can't go any faster than the ssd?
Click to expand...

1280MB/sec > 210MB/sec
Or am I missing something? :confused:
 
vincenz said:
You're not missing anything there. What you are missing is the fact that the SSDs cannot write that fast, so the speed is useless.
Click to expand...
Not useless. Sure, it won't have any advantage for SSD over SATA (other than delivering power), but it does have distinct advantages in other applications.
 
I have a need for it doing my photography. The reason LightPeak looks great is because the file imports from the external drives through USB take about an hour for 2,500 pictures.

It would take less than 3 minutes on Lightpeak.
 
Todzilla said:
I have a need for it doing my photography. The reason LightPeak looks great is because the file imports from the external drives through USB take about an hour for 2,500 pictures.

It would take less than 3 minutes on Lightpeak.
Click to expand...
No it woudn't. Lightpeak isn't going to magically make your camera (or card) transmit data faster. It may make it faster if USB is the bottle neck, but you definitely won't we moving 2,500 pictures in 3 minutes.
 
Todzilla said:
I have a need for it doing my photography. The reason LightPeak looks great is because the file imports from the external drives through USB take about an hour for 2,500 pictures.

It would take less than 3 minutes on Lightpeak.
Click to expand...

For small files like pictures, the bottleneck is your hard drive... Meaning that it will still take you about an hour to copy 2500 pictures with the same hard drive.
 
vincenz said:
You're not missing anything there. What you are missing is the fact that the SSDs cannot write that fast, so the speed is useless.
Click to expand...

SSDs can't write that fast for now. The problem is that the SSDs are progressing faster than the interface can catch up. When SSDs were becoming popular back in 08-09, it was averaging around 150MBps. Rapid innovation/optimizations have doubled that in a year or two to 250MBps (write speed) and now we're starting to get 350MBps with read performance up to 500MBps (source).

We still haven't reach mass adoption for SATA 6Gbps or USB 3.0 on Macs. The faster we can adopt to newer interface protocols like LightPeek, the better we'll be a couple of years down. USB 3.0's actual throughput (after overhead) is around ~400MBps. Which means external SSDs are already exceeding the USB 3.0's limits and look at how long USB 3.0 is slowly being adopted by Apple and other companies.

Also, LightPeek is for every type of data transfer, not just external and since LightPeek is intended to be like a *hub* for a single connection, we need all the bandwidth we can get. Imagine transferring audio/video/network/etc all over a single connection, that'll take over 1GBps easily.

As for people commenting on the photography; imagine a couple of years down with cameras using ultra-fast SSDs instead of hard drives, you'll need LightPeek to transfer the data that fast.
 
I wonder how long before we see peripherals, and if companies other than Apple have made anything already.

Would be nice is there was some external hardware to use now.
 
mac jones said:
I wonder how long before we see peripherals, and if companies other than Apple have made anything already.

Would be nice is there was some external hardware to use now.
Click to expand...

There are actually two different parts to this. LightPeek can be used as a transfer protocol, meaning that Apple can just adopt LightPeek to use USB/Firewire. It may not improve the speed from your devices but it can serve as a stopgap for now.
 
The reason LightPeak is amazing isn't that it can make any one transfer super fast, since the bottleneck would likely be whatever's doing the transferring. The beauty of LightPeak is that it can simultaneously support multiple transfers in both directions, over one connection, all at faster speeds than any one protocol that is in use today. Fewer ports, simultaneous connections, simplicity.

This means that with the use of a couple of adapters, Apple could replace all of its ports with the thinner and more versatile LightPeak ports. This includes minidisplayport, USB, firewire, everything.
 
Light Peak is 10Gb/s, which is 1.25 GB/s. the current (supposed) copper implementation, instead of fiber-optic, will top out at 16Gb/s (2GB/s). that makes it the fastest external transfer protocol available at reasonable cost.

it's important to note that current SATA III SSDs peak at 350MB/s or so in sequential. most operations are not sequential. random reads and writes don't even saturate SATA I. dramatically shorter latency and faster random 4k IO is what really makes SSDs desireable, not lofty sequential speeds.

TuffLuffJimmy said:
You can use it as a display port, as the bus between RAM, between peripherals.
Click to expand...

RAM speeds are measured in GB/s, so no, LP is not made for that.
 
toxic said:
Light Peak is 10Gb/s, which is 1.25 GB/s. the current (supposed) copper implementation, instead of fiber-optic, will top out at 16Gb/s (2GB/s). that makes it the fastest external transfer protocol available at reasonable cost.

it's important to note that current SATA III SSDs peak at 350MB/s or so in sequential. most operations are not sequential. random reads and writes don't even saturate SATA I. dramatically shorter latency and faster random 4k IO is what really makes SSDs desireable, not lofty sequential speeds.



RAM speeds are measured in GB/s, so no, LP is not made for that.
Click to expand...

That's right but can you tell me the source behind the fiber optic, my original understanding that it can top out at 100Gbps later on.

"Current" is the keyword here. We want the interface to be much faster than the "future" SSDs. Here's what Vertex 3 Pro (SandForce's SF2500) is pulling with an unoptimized fireware in 4K Random Read/Write:
http://www.anandtech.com/show/4159/ocz-vertex-3-pro-preview-the-first-sf2500-ssd/4

Write: 228MBps
Read: 330MBps

Drop down to the queue depth of 3, it's at 180MBps.

Imagine the speed with sub 10nm ONFI 3/4 NANDs two-three years from now.
 
MikhailT said:
As for people commenting on the photography; imagine a couple of years down with cameras using ultra-fast SSDs instead of hard drives, you'll need LightPeek to transfer the data that fast.
Click to expand...

What cameras use hard drives now? Unless you meant videography like the REDs? All major professional SLRs use Compact Flash cards (and some have secondary SD cards).

The limit on downloading files isn't even the hard drive or the SSD but the Compact Flash card. Camera makers are at least a year or two behind mainstream technology so it will be a long time before they are using something that is capable of a 10 Gb/s download over LightPeak.

The fastest CF cards right now are "rated" at 90MB/s or 720Mb/s but I bet that is optimistic. So even if someone made the ultimate card reader for LightPeak, downloading a 64 GB card would take > 12 minutes. (This is still a huge improvement over USB2 but it would require the fastest cards, a RAID 0 of SSD to write it, and a new card reader to be developed.)
 
TheHoff said:
What cameras use hard drives now? Unless you meant videography like the REDs? All major professional SLRs use Compact Flash cards (and some have secondary SD cards).

The limit on downloading files isn't even the hard drive or the SSD but the Compact Flash card. Camera makers are at least a year or two behind mainstream technology so it will be a long time before they are using something that is capable of a 10 Gb/s download over LightPeak.

The fastest CF cards right now are "rated" at 90MB/s or 720Mb/s but I bet that is optimistic. So even if someone made the ultimate card reader for LightPeak, downloading a 64 GB card would take > 12 minutes. (This is still a huge improvement over USB2 but it would require the fastest cards, a RAID 0 of SSD to write it, and a new card reader to be developed.)
Click to expand...

The guy mentioned using external hard drive over USB to import his photos, so in this case using external drives over LP will improve greatly. Especially from USB 2.0 on Macs (which maxes out around 20-30MBps).

http://compactflash.org/2010/cf-6-0...leading-performance-and-feature-enhancements/

CF 6.0 will top out at 167MBps.

New format in the near future will likely to top out at 500MBps by switching to PCI Express from PATA.
http://www.engadget.com/2010/11/30/sandisk-sony-and-nikon-propose-500mb-per-second-memory-card-wi/
 
MikhailT said:
The guy mentioned using external hard drive over USB to import his photos, so in this case using external drives over LP will improve greatly. Especially from USB 2.0 on Macs (which maxes out around 20-30MBps).
Click to expand...

Sorry but to a photographer, "file imports from the external drives through USB" means the file imports from the card readers before you sort them, not from external hard drives. Maybe he meant external hard drives but I'm thinking he meant CF card readers.

And while it theoretically can get faster, even the most expensive cards right now are still 90 MB/s. It will be years before there is a pro-level camera with Sony/Nikon's new format. No way it happens in the "near future".
 
TuffLuffJimmy said:
Not useless. Sure, it won't have any advantage for SSD over SATA (other than delivering power), but it does have distinct advantages in other applications.
Click to expand...

here the catch 22, what if you could set up a raid of SSDs say the size of the external power Supply, the reads/writes could be on parallel SSDs giving you the max bandwidth to and from the SSDs.:)
 
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