In terms of BW calculation, this I can only leave up to RME. BTW, AFAIK the whole amount of channels (30in/30out) will instantly be transferred by the driver, no matter how many you use.

There is no limitation, otherwise the UFX would have sucked since over a decade and this is not the case
UFX and UFX II have the same amount of channels and for this USB2 is sufficient otherwise it wouldn't have worked for over a decade.

I was using the UFX for ~4 years and also got RayDAT (PCIe) and 2x UFX+, ADI-2 Pro. All RME devices are absolutely reliable and deliver a phatastic performance even with lowest ASIO buffer sizes.

I am also doing latency critical recordings using a guitar plugged to UFX / UFX+ to drive a virtual amp (Kuassa) in some projects and I can use ASIO Buffersizes up to 256 (but that is the "edge" 128 feels more comfortably) without noticing any delay that slows down your playing which is the case when you hear the Amp too late (signal coming from DAW via USB).

I collected the Round trip times that the ASIO driver reports to the DAW in one of my blog articles. From this excel tabular you can see, that USB, Firewire, USB3, Thunderbolt interfaces are ALL absolutely on par with PCIe based products like the RayDAT.

And even when making performance comparison between UFX+ and RayDAT with a 400 tracks Cubase project (consumes 28GB DRAM on my Win7 machine), where each track has 3 inserts (VSTs) and I can use the smallest ASIO Buffersize with UFX+ and RayDAT without noticing any significant / visible difference in terms that "USB requires more CPU resources". This article is also available in english, scroll down, behing the german part.

At the end of this post the relevant links.

> Why then people still complain/resent "RME uses prehistoric USB 2.0 technology in UFX II flagship"?

Could you kindly post a reference, where this has been said ? That would be interesting.
I never saw something like this.

And whats more important, I never experienced any limitation with USB2 of my UFX which I used for a long time.

Here the references:

1. http://www.tonstudio-forum.de/blog/inde … 8-RME-UFX/

In this article about UFX+ you find an excel with the different RTT times.
For the UFX (that I had before the UFX) there are 3 use cases: USB, FW and as Preamp in front of the RayDAT.
RayDAT is a purely digitally working card so for fairness you need to add the time for the D/A conversion part to be compareable with the UFX.

2. http://www.tonstudio-forum.de/blog/inde … cks-de-en/

And what people also forget, they should be thankful that RME designs the interface to the actual demand and not for "marketing paper" reasons.

USB2 on i.e. the UFX II is a benefit for users:

• on systems where i.e. the amount of USB3 ports is still a valuable resource (low)

• on systems where you even do not yet have USB3

• As you can connect the UFX II to either USB2 or USB3 ports (in USB2 compat mode). So if somebody is having issues with USB on his system (maybe caused by design / BIOS / USB controller / interference with other USB devices), this gives you more options to find a port where the UFX II is the only device behind an USB controller so that audio is not disturbed by the transfers of other devices.

And if you should require to expand your system with an PCIe USB card, because you do not get rid of USB problems on your particular mainboard (which also can happen in rare cases), then you have the choice of either expanding the PC with either USB2 or USB3. I personally would prefer USB3 so that you do not fill a valuable PCIe socket with older USB2 ports. My UFX with USB2 worked i.e. perfectly on an USB3 port which came from the Intel C612 chipset.

1st of all take same sample rate of 44.1 thanks.