iMac i5

[OneWorld]

I like a tinker about and have been offered an iMac i5 1TB, 16gig ram, 27" 5K retina display, with Catalina for what I think is a good price £375, just has a slight scratch on the frame, not on the screen

Would this make a Decent DAW. I am particularly interested in the fact it has 2 thunderbolt connectors and I am keen to move away from Firewire and think the Thunderbolt bus is far faster than USB and as far as DAWs are concerned - the way to go?

[Sam Spoons]

It's probably faster than my 2008 Mac Pro and that price sounds decent. WRT Thunderbolt vs USB I wouldn't worry about it, USB2 is clearly fast enough for many more input and output streams than most people need. 32 x 32 of 16 bit 48kHz is certainly doable over USB2.

[OneWorld]

It's probably faster than my 2008 Mac Pro and that price sounds decent. WRT Thunderbolt vs USB I wouldn't worry about it, USB2 is clearly fast enough for many more input and output streams than most people need. 32 x 32 of 16 bit 48kHz is certainly doable over USB2.

Right thanks, a 2008 Mac Pro still going strong, that's a good enough sign as to the durability

[s_e_a_n]

I'm still using a 2014 1st gen 5k iMac as my main machine running Logic (which now requires a newer OS version to upgrade) and DP10 with no problems. I would love to upgrade to a better machine but the tiny speed bumps since have not been worthwhile (other than the iMac Pro which was a bit too expensive) and the M1 iMacs are only 24". I'm sure when they come out with a bigger M1 iMac I'll upgrade and then spend the next couple of years cursing Apple for the new range of problems I'll encounter

[Sam Spoons]

It's probably faster than my 2008 Mac Pro and that price sounds decent. WRT Thunderbolt vs USB I wouldn't worry about it, USB2 is clearly fast enough for many more input and output streams than most people need. 32 x 32 of 16 bit 48kHz is certainly doable over USB2.

Right thanks, a 2008 Mac Pro still going strong, that's a good enough sign as to the durability

I have two 2008 Mac Pros, They've been good but not completely trouble free (the reason for having two) I replaced a memory board in the other a couple of years ago and that one started crashing recently, probably due to overheating but I haven't got to the bottom if the issue yet. But they are pretty fixable and, as there seem to be plenty of used spares out there, reasonably cheaply fixable. The iMac OTOH is not such an easy DIY repair. But for the money that still sounds like a proposition to me.

[OneWorld]

It's probably faster than my 2008 Mac Pro and that price sounds decent. WRT Thunderbolt vs USB I wouldn't worry about it, USB2 is clearly fast enough for many more input and output streams than most people need. 32 x 32 of 16 bit 48kHz is certainly doable over USB2.

Right thanks, a 2008 Mac Pro still going strong, that's a good enough sign as to the durability

I have two 2008 Mac Pros, They've been good but not completely trouble free (the reason for having two) I replaced a memory board in the other a couple of years ago and that one started crashing recently, probably due to overheating but I haven't got to the bottom if the issue yet. But they are pretty fixable and, as there seem to be plenty of used spares out there, reasonably cheaply fixable. The iMac OTOH is not such an easy DIY repair. But for the money that still sounds like a proposition to me.

Yep, I inclined to buy it and try it, then if not quite what I expected then sell it on. And maybe see how the M1 Macs develop. Having said that, my PC is quite acceptable, Win10 is (cross fingers) trouble free, reasonably fast. The iMac is attractive because of the price and is something else to tinker with

[Sam Spoons]

Do bear in mind that if you buy a Mac there is a risk you will get sucked into the Apple ecosystem I don't see me ever going back to Windows, OSX is not faultless and intuitive (whatever the Apple fanbois say) but it generally does what you want in a relatively fuss free manner.

[Eddy Deegan]

What year is it from? We recently bought a 27" iMac second hand from a friend of a friend for £100. The latest OS it can run is Catalina.

Browsing is broken, you can't upgrade Safari, Firefox won't install on it, Chrome does but a lot of websites are kind of broken (there seems to be an issue with anything involving HTTPS/SSL).

The only things I can say about it that are positive are that it's got a lovely screen, access to all the old stuff I bought on iTunes back in the day and that it's good as a basic family computer running non-Apple software for the kids.

As a DAW, not even close. Apple seem to have condemned some otherwise perfectly good hardware to obsolescence and there's no practical way around that.

As Apple TV is also available on the Amazon Firestick now, I'm almost certainly going to nuke OS X on the iMac and install Linux in some form or other.

[Sam Spoons]

Catalina had a rep for being troublesome but I'm running El Capitan (OSX 10.11 which is the latest it will run) on the 2008 and both Safari and Brave seem to work fine on it. Have you tried running Mojave or High Sierra, I have the latter on my 2012 MBP and likewise Sierra and Brave work fine?

I keep trying Linus but lose patience before I can really get to grips with it. I guess learning yet another OS is too much hassle for me

[merlyn]

I am particularly interested in the fact it has 2 thunderbolt connectors and I am keen to move away from Firewire and think the Thunderbolt bus is far faster than USB and as far as DAWs are concerned - the way to go?

Are you sure it's Thunderbolt? It may well be, but it's worth checking as Thunderbolt looks the same as mini Display Port, which has been on Macs for longer.

Also on the subject of 'fast' -- there's bandwidth (what USB 3 has more of than USB 2) and latency (exactly the same on USB2 and USB3). Focusrite have explained this possibly subtle distinction in this article :

https://support.focusrite.com/hc/en-gb/ ... t-USB-3-0-

Useful Analogy

A good analogy is to think of it as a drainpipe and a tennis ball. The tennis ball is the data, and the width of the pipe signifies available bandwidth. With the drainpipe set at the same angle, letting go of the ball at the top of the drainpipe will see it arrive at the bottom in a given amount of time. That's your latency, the time it takes to go from end to end.

In terms of our analogy, USB 3.0 offers a much wider pipe. This means that it could allow a greater number of tennis balls (more data) to travel down the pipe, but the balls would not travel down the pipe any faster– there is no latency improvement. This is the same when comparing USB 3.0 and USB 2.0 in terms of the way they transfer audio data.

So for Thunderbolt it undoubtedly has more bandwidth you don't need, but is it faster?

[Kwackman]

If it's running Catalina, it will probably be this one at least, or perhaps a newer one.
https://everymac.com/systems/apple/imac ... #macspecs1
If so, they are thunderbolt ports.
I think Apple put a little lightning symbol on thunderbolt ports to distinguish them from the mini display port which has a different symbol, even though the ports look the same as Merlin stated.

The above info is given with no certainty!
Sounds like a nice iMac though.

[OneWorld]

I am particularly interested in the fact it has 2 thunderbolt connectors and I am keen to move away from Firewire and think the Thunderbolt bus is far faster than USB and as far as DAWs are concerned - the way to go?

Are you sure it's Thunderbolt? It may well be, but it's worth checking as Thunderbolt looks the same as mini Display Port, which has been on Macs for longer.

Also on the subject of 'fast' -- there's bandwidth (what USB 3 has more of than USB 2) and latency (exactly the same on USB2 and USB3). Focusrite have explained this possibly subtle distinction in this article :

https://support.focusrite.com/hc/en-gb/ ... t-USB-3-0-

Useful Analogy

A good analogy is to think of it as a drainpipe and a tennis ball. The tennis ball is the data, and the width of the pipe signifies available bandwidth. With the drainpipe set at the same angle, letting go of the ball at the top of the drainpipe will see it arrive at the bottom in a given amount of time. That's your latency, the time it takes to go from end to end.

In terms of our analogy, USB 3.0 offers a much wider pipe. This means that it could allow a greater number of tennis balls (more data) to travel down the pipe, but the balls would not travel down the pipe any faster– there is no latency improvement. This is the same when comparing USB 3.0 and USB 2.0 in terms of the way they transfer audio data.

So for Thunderbolt it undoubtedly has more bandwidth you don't need, but is it faster?

Yes but the more tracks, the more tennis balls can pass along. Do they travel in parallel or serial. If there is a train with 4 full carriages travelling down the track at 100mph, it is the same as 4 trains each pulling one carriage, at 25mph, the distance will be shorter, one train length v 4 trains length, hence shorter latency. I thought that was the advantage of FireWire over usb (Universal ‘Serial’ Bus) I believe FW maintained a consist speed whereas USB peaked at a given speed, essentially the data ebbed and flowed.

Ok, all this is academic, as far as I know even USB2 can transfer data fast enough for even the most demanding DAW use. But, if USB2 and beyond exceeds demands, why bother ‘inventing’ Thunderbolt? What were the shortcomings of USB that inspired the development of Thunderbolt?

[OneWorld]

What year is it from? We recently bought a 27" iMac second hand from a friend of a friend for £100.

I am told it is mid 2015. It has the Retina Display and is 5K display. I am lead to believe the Retina Display before 2015?

[Sam Spoons]

Ok, all this is academic, as far as I know even USB2 can transfer data fast enough for even the most demanding DAW use. But, if USB2 and beyond exceeds demands, why bother ‘inventing’ Thunderbolt? What were the shortcomings of USB that inspired the development of Thunderbolt?

Thunderbolt and Firewire were not developed so that a few itinerant musos could record a few more tracks simultaneously they were developed so that external storage devices could shift huge amounts of data to and from a computer faster.

[merlyn]

I thought that was the advantage of FireWire over usb (Universal ‘Serial’ Bus) I believe FW maintained a consist speed whereas USB peaked at a given speed, essentially the data ebbed and flowed.

Everything is serial these days. You may remember IDE hard drives with ribbon cables -- that's parallel -- multiple wires. Kind of a relief to have them replaced with SATA -- serial ATA. If you've ever hacked up a USB cable you will know it has four wires -- two for power and two for the signal, and all these formats use serial because it involves less wires.

My understanding is that the advantage Firewire offers over USB is that the controller chip does more of the work, meaning less CPU overhead. This was back in the days of USB 1.1 when USB audio was ... eh ... there's no other word for it ... bad. That impression has been hard to shake for me and I still use a PCI card.

USB audio goes at a constant speed. It's called isochronous transfer -- with USB 2 eight packets are sent per millisecond. These are the tennis balls. The latency due to USB is then a minimum of 0.25 milliseconds or 12 samples at 48kS/s.

When I asked about Thunderbolt it was a genuine question as I don't know about the inner workings. If anyone does, please share. I think a Thunderbolt interface will probably have good latency, but that may not be due to Thunderbolt itself. A Thunderbolt interface will be newer, and most Thunderbolt interfaces at the moment are pretty high end, so they're likely to have had some effort go into the drivers.

But, if USB2 and beyond exceeds demands, why bother ‘inventing’ Thunderbolt? What were the shortcomings of USB that inspired the development of Thunderbolt?

Four channels of MADI would do it. That's beyond what USB 2 can do.

[jjlonbass]

Thunderbolt is an interface with multiple personalities - depending on generation, it can support PCIe, DisplayPort and, from generation 3, USB 3 modes.
If the Mac in question is from 2015 it is likely to have Thunderbolt 2 ports which have a 20 gigabit / second data rate supporting 4 PCIe 2.0 lanes or DisplayPort 1.2.

Thunderbolt 2 in its PCIe mode is much faster than Firewire and USB 3.2 as its 4 PCIe lanes provide an aggregate 2000 Mbytes / second bandwidth and a more or less direct connection to the computer's memory and CPU interconnect.

Note that each lane of PCIe is also serial in nature like USB, SATA etc.

The advantage that Firewire had over USB in terms of CPU overhead only applied to the early UHCI host controller type used for USB 1.1. From USB 2.0 onwards, the host controller hardware does nearly all the work. There is some detail here.

John

[merlyn]

Thanks John. So Thunderbolt is like bringing the PCIe bus outside the computer. That has the potential to be a low latency solution.

Thunderbolt's bandwidth can do thousands of tracks, so that's total overkill. The latency may be better. If anyone has comparative figures that would be interesting to see as I suspect the latency difference between a Thunderbolt and comparable USB 2 interface would be small.

It's also worth bearing in mind that if the latency is below 5ms it's not noticeable, to me anyway. So there's not a lot of point in paying £2000 to go from e.g. 4ms to 2ms

[OneWorld]

Thanks John. So Thunderbolt is like bringing the PCIe bus outside the computer. That has the potential to be a low latency solution.

Thunderbolt's bandwidth can do thousands of tracks, so that's total overkill. The latency may be better. If anyone has comparative figures that would be interesting to see as I suspect the latency difference between a Thunderbolt and comparable USB 2 interface would be small.

It's also worth bearing in mind that if the latency is below 5ms it's not noticeable, to me anyway. So there's not a lot of point in paying £2000 to go from e.g. 4ms to 2ms

I take that point - is it worth paying all that money for an almost un-noticeable change. But from what I have experienced, there are many interfaces that happily get down to 64 samples. But add a batch of audio tracks, the CPU heavy VSTi that cane the CPU and that 64 samples is has to be cracked back to 256, and even then there can be crackles. I am under the impression that Thunderbolt wouldn't even break into a sweat, right down to 32 samples?

[jjlonbass]

Yes, Thunderbolt's PCIe mode brings a PCIe link to the outside world.

Note that PCIe isn't a bus - it's a packet switched network in a similar fashion to 100 Mbit and upwards Ethernet.

Latency approaches zero and is governed by the sum of the length of payload data to be sent per transaction and the transaction packet overhead. As an example as detailed here, a packet with 128 bytes of payload data and 30 bytes of overhead can be sent in 75 nanoseconds over a 4 lane link, so the latency in this case would be 150 nanoseconds.

John

[merlyn]

I am under the impression that Thunderbolt wouldn't even break into a sweat, right down to 32 samples?

Certainly if a Thunderbolt interface is using a 32 sample buffer and gets pops and clicks (xruns) it's not Thunderbolt that's the problem.

In your case have you tracked down the bottle neck to the interface? Decreasing the buffer size means less plugins and virtual instruments can be used, there's no way around that. Is it the CPU that's getting maxed out?

There is an old thread comparing latencies on different interfaces :

https://www.soundonsound.com/forum/view ... hp?t=24765



OK, so it's a bit old, but it does give us an idea of what's going on. First, top of the list is a PCIe card -- that's the reference system. Second, there is a direct comparison between USB and Thunderbolt with the RME UFX+. There's not a lot in it. The latency performance includes how low the buffer will go, but also what you're talking about -- how much an interface can do at low buffer settings.

Thunderbolt sounds like a good approach, as PCIe is the fastest that can be had, but in practice the difference may not be noticeable. There is also variation between Thunderbolt interfaces, so if you were looking for a new interface it would be best to check them out on an interface by interface basis.