Quality wise there is really not much difference, if audible at all. I have one of the oldest RME converter designs and they sound great. So go for the features you need or might need in the foreseeable future.

If you definitively NEED smaller formfactor or are limited by budget go UCX.

Otherwise go UFX II or even UFX+ if you shall need MADI.
Its worth alone for Durec and the standalone capabilities of UFX II or UFX+.
UFX II is the same like UFX+ except MADI, USB3/TB.

My blog article collects the changes between old flagship interface UFX and UFX+.
https://www.tonstudio-forum.de/blog/ind … 8-RME-UFX/

Here an overview sheet to compare the interfaces:
https://www.tonstudio-forum.de/index.ph … 017-12-pdf

A MADI setup is nice, sorry only available in German: https://www.tonstudio-forum.de/blog/ind … Cber-MADI/

Its true that the UFX+ has to transport all channels through USB3.
For a normal PC this is no issue. You need to take the USB ports that come from chipset.
Shall you have issues, then isolate the USB traffic for recording by getting Sonnet card with FL1100 chip.
The drivers use a more efficient driver model (msi, message signalled interrupts).
I did even take a Sonnet card with 4 dedicated FL1100 chips (4 x Full USB3 BW!!!)
Therefore the card requires 4 PCIe lanes.

I can now easily drive two (!) UFX+ in parallel and an ADI-2 Pro.
With project sizes like this:
https://www.tonstudio-forum.de/blog/ind … cks-de-en/

On a PC like this:
https://www.tonstudio-forum.de/blog/ind … mponenten/

But even a much smaller PC will do ... maybe not the 400 tracks, but at the end to drive the UFX+.

Hardware requirements and USB compatibility, see handbook.
At minimum, Intel Core i3 CPU ... well thats doable, isnt it ?!

Not necessarily required, but it makes sense to isolate the USB3 audio traffic to a separate card:
https://www.heise.de/preisvergleich/son … 79334.html
Then you need a PCIe x4 socket.

If you only want to connect 1 audio interface, then this is sufficient, where 1 controller is shared by 4 ports:
https://www.heise.de/preisvergleich/son … 48037.html
Then you only need a PCIe x1 socket.

The advantage is, if you connect hubs and bluetooth devices and this and that to the USB ports driven by your chipset then it can sometimes come to kind of let me say "interferences" that I got i.e. audio drops when using the USB Bluetooth adapter.

Now where I have the two UFX+ and the ADI-2 Pro behind the Sonnet card, I can connect USB devices like I want to the PC and there are no issues with the recording interfaces anymore.

I think I can at least make that statement without being too wrong ...
The amount of channels is not that critical if you do not have an ancient PC or a "crippled"/misdesigned mainboard/BIOS.

If you take the UFX II / UFX+ you will benefit from latest design, very short:
- better analog section
- more modern MADIface driver which allows down to 32 samples ASIO buffer size

For some systems it might be easier to find enough USB2 ports (Laptops).
UFX+ is simply a question of requirements (amount of channels, MADI) and whether you have the budget.

I see a big benefit in MADI, as you are more flexible in cabling and use of MIDI via MADI.

And when you would like to add i.e. 2 Octamic XTC to the system, you can run even up to 192 kHz without loosing channels.

With ADAT you loose already 50% of channels with 88.2/96.

MADI has 64 channels ... you can run up to 4 Octamic XTC with additional 32 channels @88.2/96.
and if you are a "freak" ^h^h^h^h^h^h^h^h think you require 192 kHz ...
you can connect 2 Octamic XTC with additional 16 channels @192 kHz without loosing a channel.

More flexibility compared to ADAT and the ADAT channels you have still free for other stuff, i.e. to connect an ADI-2 Pro or your HiFi via long TOSLINK cable.

BTW, at least in Germany the UFX+ cost now €200 less .. so only €400 more compared to UFX II .. nice price !

I would get UFX+ and eventually get also the add on card with one or four FL1100 to proactively isolate the UFX+
and fix any potential side effects of other connected stuff via USB.
If this doesnt work, try to use USB ports from chipset or TB if you have.
If this does not work, then send it back as you might not want to upgrade your PC as well.
Order then UFX II as an alternative, with this recording interface your system should not have any issues when using the supported USB ports from Iintel or AMD) chipset.

What do you mean by faster ?

And to sum up from my side .. when looking at your older threads
https://www.forum.rme-audio.de/viewtopic.php?id=26226
I remember your issues and there were already statements, that your machine / setup is broken.

At least from my side I had to day, that a PC with Virtualization Stuff installed, which changes a lot inside of Windows is definitively not the way to go to build a stable recording platform !!! ESPECIALLY if you want to record at 96 kHz.

Maybe even Sonar is not the best choice as DAW product.
And I think you tested already that another DAW worked better.

Don't get me wrong, but I think these discussions here in this thread lead simply to nowhere ("UFX* vs UCX") and we are going in circles, as I think the root causes lie somewhere else.
I demonstated you in the old thread already, that with my machine I have no issues to run a 400 track project with a VST in each track either in 44.1 or 96 kHz ....
https://www.tonstudio-forum.de/blog/ind … cks-de-en/

So my questions to you are:

1. Did you try using USB2 with the UFX+ as suggested by MC ?
This will automatically limit the amount of channels to be like on an UFX II (all but MADI) ?!

2. Do you have now a normal Win7 installation optimized for audio without Virtualization / Development tools installed ?

3. Did you try the Sonnect card, see my signature with more efficient MSI interrupt handling causing fewer interrupt load on the system ?

4. Did you try using a different DAW which works more efficient and where you can freeze VSTis like Cubase ?

5. Does everything work better at 44.1 ? Or is it an option to freeze VSTis in Cubase and to work with 96 kHz ?

Re-edited: 04.08.18 10:38 pls re-read.

You expect answers for things that nobody can easily and exactly tell. The majority of customers do not have these kinds of problems.

Whether the Sonnet card gives you advantages over Thunderbolt is not predictable, but you could have tried. Google for "MSI" (message signalled interrupts). I think its a chance as it fixed my problems as well which arose when I added on top of the 2 UFX+ and ADI-2 Pro too many additional USB periphery like Bluetooth adapter, USB3 hub. So I think under certain conditions it still makes sense to fully isolate recording interfaces behind a dedicated controller (be it USB or Firewire).

Strange is the thunderbolt didn't solve the issue, which makes me think whether other surrounding conditions either cause or simply add to the problem (as you said it became better, but was not gone entirely). Somehow it seems to be load related as you have no issues with smaller projects.

You are recording at 96 kHz which definitively puts more stress to a machine (CPU, interrupt and i/o related).
Maybe your system is overloaded for the things that you intend to do, be it CPU or whatever.

I told you try Cubase and to freeze VSTis, but you didn't check. And if 96 kHz is not possible I would simply pragmatically use 44.1 kHz, which in most cases is fully sufficient. I doubt that you will hear any differences. People use 88.2/96 mostly for recording of classical music.

The best might be, that you consult a PC specialist for Audio Workstations like Xi Machines in Germany, they will surely also sell to outside of Germany. They can give you then consultancy what you require and then I am pretty sure you can enjoy every RME recording interface. Maybe a better / cleaner approach than playing trial end error for too long.

The machine simply need to have a good and proven design (i.e. in terms of mainboard / BIOS) and components, then also enough CPU power for the type of projects that you use. You need to discuss with them whats more required for your type of project. Single thread performance or the number of cores. This might also be depend on the DAW that you use.

I personally would recommend to check out Cubase Pro, as there you can freeze projects easily (but still changing gain, panning, etc) which is a simple but very important possibility to reduce CPU load in any project.

Maybe you are also doing mistakes in your workflow, that you mix with already putting mastering plugins into the project. Maybe a strict separation of Mixing, Downmix and then mastering only with one stereo track - which is the recommended workflow anyway- would also help.

I had really good luck with my system as I got a tip in a recording forum to take Xeon based systems with Supermicro mainboards (being used in the enterprise sector where you need to have reliability to be able to hold your SLAs as an integrator and vendor). Many builds of Xi-Machines seem to be based on Supermicro boards and Enterprise components.

UFXII is the same as the UFX+, at lower price tag for people who do not require MADI.
For 30 channels you do not need USB3 and Thunderbolt, therefore the UFX II has USB2.
RME makes it possible with their drivers to send up to ~66 (EDIT: IN and OUT) channels via USB2 (MADIface Pro), so with the UFX II and USB2 you are really safe.

The UFX+ and UFXII have the latest converter and the audio section has been enhanced compared to the old flagship UFX.
They use the latest MADIface driver which allows for even smaller ASIO buffer sizes (32) compared to UCX/UC/UFX.

I personally had the impression that the analog section of the UFX+ (and thus UFX II) has improved compared to the UFX (former flagship), by this I can only assume that it's also better compared to the UCX.

If you have the money get the UFX II, it's a "no brainer". There you have enough input and output channels for your synths and on top a little bit more. Whats also nice is the DURec functionality where you can record in parallel to DAW or even completely standalone. Standalone operation has also been enhanced, (EDIT:) as well as DURec (real time clock, timestamps for files on DURec media, etc). Complete list of enhancements of UFX+/UFXII over the old flagship UFX, see my blog article: https://www.tonstudio-forum.de/blog/ind … 8-RME-UFX/

The PCIe card is only an optional recommendation for the UFX+ (and its high channel count).
But only in cases where you have much other USB peripheral stuff connected, also USB Blootooth adapters and alike.
Because on my system this produced at the end audio drops, therefore I needed the card to fully isolate the UFX+ behind the dedicated USB controllers of that card. And I was using even two UFX+ and an ADI-2 Pro.

Usually you will not require the extra Sonnet USB3 PCIe card. Another nice thing of this card, though, it uses the more efficient Message Signalled Interrupts (MSI) which has advantages on a loaded system with high interrupt load.

I would recommend you the UFX II in the 1st place, it has an enhanced audio section, latest converters, latest drivers.
If this is not feasible, then take the UCX.

Best is you get both, try them out and then decide.

The USB3 ports recognize when an USB2 device is being connected and fall-back to USB2 mode.
But I am not sure whether this really works for all USB3 chipsets.
From what I know and read in the RME manuals you are always on the safe side with USB ports, that come from the mainboards chipset (Intel or AMD).
In the UFX+ manual the Fresco Logic USB3 controller (FL1100) is mentioned to be compatible to the UFX+.
I bought the Sonnet card because it has the FL1100 USB3 controller on board and because I regard Sonnet as a good company.
BTW, I edited a few things in the previous post (#12) and also added a link to a blog article from me, which lists all the improvements of UFX+/UFXII over the old flagship.
I think the UFXII / UFX+ are the best interfaces you can get on the market, round package, solid and offering a feature density that is outstanding, worth every cent.