Andrewr05 Posted May 19, 2009 Posted May 19, 2009 I'm sitting here thinking of USB 3.0 (premiumgfx' news post made me think of this) and I was wondering about speed. Since 2.0 can achieve a lot higher speeds than 1.0 does that mean that a 1.0 device plugged into 2.0 architecture is running at its maximum speed? A 1.0 device has a data rate of 12 Mbit/s and 2.0 can achieve 480 Mbit/s, so I'm assuming since 12 Mbit/s is such a fraction of 480 Mbit/s that it is always maxed out. Now on to 3.0, if we assume the same thing, 3.0 runs at 5 Gbit/s (theoretical) and since 2.0 is 480 Mbit/s I can only assume that if we all upgrade to USB 2.0 gear that we will all be maxing out our 2.0 potential. Obviously not all 2.0 hardware can even achieve 480 Mbit/s, but assuming it could can current 2.0 hardware sustain 480 Mbit/s all the time? yeah, noob questions... I'm literally out the door for work right now... so errr... yeah... TTYL bye cya etc... *grabs sweater, runs for door* Quote Share this post Link to post Share on other sites More sharing options...
hardnrg Posted May 19, 2009 Posted May 19, 2009 http://en.wikipedia.org/wiki/USB#USB_signaling Quote Share this post Link to post Share on other sites More sharing options...
Andrewr05 Posted May 19, 2009 Posted May 19, 2009 At a quick glance I don't see how that answers my question... Quote Share this post Link to post Share on other sites More sharing options...
hardnrg Posted May 19, 2009 Posted May 19, 2009 A USB1.0 device operates in USB1.0 signalling mode, regardless of the USB port capabilities... If the device supplies enough packets, the maximum data rate (of USB1.0 signalling mode) can be achieved, otherwise a lower data rate is attained. I don't really understand what you are asking as I can't see a clear question. But USB3 won't make USB2.0 devices faster if that's what you are asking Quote Share this post Link to post Share on other sites More sharing options...
slugbug Posted May 19, 2009 Posted May 19, 2009 (edited) How many USB 2.0 devices are there out now which don't even transfer at USB 1.0 speeds. I doubt we'll see many if any USB 3.0 devices which even come close to reaching the specs rated speeds. Theoretical speeds don't mean . in the real world. Edited May 19, 2009 by slugbug Quote Share this post Link to post Share on other sites More sharing options...
slick2500 Posted May 19, 2009 Posted May 19, 2009 (edited) I thought USB 3.0 was supposed to be wireless like bluetooth? Or maybe I read something wrong. Edited May 19, 2009 by slick2500 Quote Share this post Link to post Share on other sites More sharing options...
Fight Game Posted May 19, 2009 Posted May 19, 2009 (edited) Isn't that just the maximum possible speed of the interface, kinda like hard drives? remember ata100 drives doing 33, ata133 doing 40, sata150 doing 60, sata 300 doing 65 lol Just because the maximum speed of the interface increases doesn't mean anything will ever be faster. Edited May 19, 2009 by Fight Game Quote Share this post Link to post Share on other sites More sharing options...
Andrewr05 Posted May 19, 2009 Posted May 19, 2009 A USB1.0 device operates in USB1.0 signalling mode, regardless of the USB port capabilities... If the device supplies enough packets, the maximum data rate (of USB1.0 signalling mode) can be achieved, otherwise a lower data rate is attained. I don't really understand what you are asking as I can't see a clear question. But USB3 won't make USB2.0 devices faster if that's what you are asking I guess I was confused and being confusing at the same time. What I was wondering is whether or not a USB 2.0 device will run at its maximum speed constantly on USB 3.0 hardware? For instance a USB 1.0 USB drive probably wont reach its potential on USB 1.0 hardware. However that same drive plugged into a USB 2.0 port probably sustains its maximum throughput easier on USB 2.0 hardware because of the headroom. My question is would USB 3.0 allow USB 2.0 drives to achieve their maximum speed more often? I dunno, I'm making less and less sense the more I try to explain it... Quote Share this post Link to post Share on other sites More sharing options...
jammin Posted May 20, 2009 Posted May 20, 2009 But USB3 won't make USB2.0 devices faster if that's what you are asking See above. Think of them as separate things basically. Backwards compatibility just means that previous devices will work just how they used to. Quote Share this post Link to post Share on other sites More sharing options...
Kash Posted May 20, 2009 Posted May 20, 2009 USB 3.0 isn't going to make USB 2.0 magically run at 100% throughput just like how USB 2.0 doesn't make USB 1.0/1.1 to run at 100% throughout. It's just not how the technology was designed. Firewire, on the other hand, will most likely do what you're asking since that technology was better designed for sustained throughput (USB is more of a burst technology rather than sustained throughput) Quote Share this post Link to post Share on other sites More sharing options...
Andrewr05 Posted May 20, 2009 Posted May 20, 2009 I wish I could word this better. I know that a USB 2.0 device can not go faster than 480 Mbit/s and I'm sure that most USB 2.0 devices do not even reach that. I was merely wondering if USB 3.0 would allow the USB 2.0 device to reach its maximum speed (480 Mbit/s and under) more often. or am i just a complete noob? ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ I guess its computer dependent as well, because from my standpoint the transferring of data through USB is pretty CPU intensive... With a USB 3.0 card installed in your computer you would think because it can transfer a lot more than 480 Mbit/s that the computer wouldn't be straining to attain the higher speeds of USB 2.0 spec. Okay now for a horrible horrible analogy... Take a town car (a crappy car that you would drive around town) and put it onto a racetrack. That car can not go any faster than it is absolutely designed to. However that race track allows the car to reach a higher average speed because its architecture is designed for faster speeds than a town road. The track isn't allowing the car to go faster than it is capable of, it is merely allowing the car to achieve its maximum speed more often. USB 1.0 spec = town roads USB 2.0 spec = racetrack with a 1 mile straight away USB 3.0 spec = racetrack with a 10 mile straight away Plug a USB 1.0 device into a 2.0 port and that device should be able to maintain 12 Mbit/s (or whatever its maximum speed is) longer than if it was plugged into USB 2.0, correct? Maybe I'm just retarded.... USB 3.0 isn't going to make USB 2.0 magically run at 100% throughput just like how USB 2.0 doesn't make USB 1.0/1.1 to run at 100% throughout. It's just not how the technology was designed. Firewire, on the other hand, will most likely do what you're asking since that technology was better designed for sustained throughput (USB is more of a burst technology rather than sustained throughput) That is exactly what I was wondering... I just couldn't word it coherently. So there is essentially no speed increase at all? I wasn't expecting 100% of the maximum throughput but at least a bit of an increase... Quote Share this post Link to post Share on other sites More sharing options...
Kash Posted May 20, 2009 Posted May 20, 2009 Maybe I'm just retarded.... I'm gonna go with this sentiment Quote Share this post Link to post Share on other sites More sharing options...
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