Hello!

You can try these tweaks for your system to relieve some more load from the CPU:

- Disable C-states in the Bios
- Highest perfomance settings(Windows)
- Optimize for Background tasks(Windows)
- Disable unnecessary windows services.

Also, open Device Manager -> USB controllers
Right click on every usb hub(or if you can pinpoint your specific USB por for the BF Pro FS) -> Properties -> Power Mangement and uncheck "Allow computer to turn off this device" option.

If you 've, already, done these, you could try disabling any heavy effects from each vst, like reverbs(especially convolution ones)

If it is about sampler vst playback, only output latency is relevant IMHO. I can play piano in kontakt at 256 easily. I prefer 64 or 128 but to be honest 256 feels the same. 10ms output latency is indeed unplayable with percussive sounds like piano or drums. Pads and slow strings are fine.
Btw I have a bf pro FS too. And it performs only a very little bit worse then my RME PCI cards. Only under very heavy load you might get a crackle a little sooner. But latency itself is the same. Even 0.x ms worse on my hdsp9632.

If I use this VST (sunburst) at 64 samples, it only cracks (in Melody mode, not pattern), I guess the samples are very very high quality compared to others VST.
https://www.native-instruments.com/en/p … -sunburst/
And with others VST with very high quality samples it cracks,  some presets in Nexus 3 crack too.
I have finally found that 44.1khz, 128 sample, and total latence of 7.05ms is good

I don't know, but I guess the very very high quality  samples from Native Instrument is the issue (and it's not an issue, the top quality is a pleasure) but at 64 samples, no way to handle this VST in Melody mode, even if many others 'lights" VST work at 64 samples...With this VST I have found that 128 samples 44.1khz works, and 256 samples 48khz works too.

Not getting your point, what "card" is a monster ?

Ah ok. If I hear card I always think of a PCI/PCIe card. But maybe its kind of "jargon".

This question doesn't make to me much sense as all RME drivers have a very low latency in terms of
- RTL (round trip latency)
- AD/DA converter latency (which is anyway much lower compared to RTL)

More critical is the PC side in terms of HW and settings with good drivers resulting in lower DPC latency and a more agile computer which makes it possible to use lower ASIO buffer sizes in many cases.

As you can see from my blog article, the RTL (round trip latency) between different RME products with different drivers and setups (ADAT, MADI) are pretty much on par and the differences are not that high.

Look more that you get the features / flexibility that you need.
You can compare interfaces / features with my Excel that you find in this blog article:
https://www.tonstudio-forum.de/blog/Ent … B-MADIfac/
Direct Link to Excel: https://www.tonstudio-forum.de/attachme … 4-08-xlsx/

It's always good to have some spare ports.. The more ports you have as spare the more ports you have for e.g.
- loopback (if needed, without sacrificing ports that you need to connect devices) or
- to split audio from PC to TM FX SW playbacks (*)
- with more analog I/O ports you can connect external devices
- with two ADAT ports you can connect external devices (preamps, AD/DA converter) with 8 ports also at double speed
- with an additional spare AES ports you can later add high grade converters like ADI-2 Pro FS R BE and still have ADAT to add external preamps or AD/DA converter
- with MADI you can add more devices allowing up to 2km between each of the devices in a serial chain of MADI devices allowing better placement of devices to e.g. different recording rooms, etc

(*) The more SW playback channels you have the more you can customize the monitoring for monitors and phones.

IMHO the best USB interfaces are:
- BBF Pro (main focus mobility and quality)
- UCX II (Autoset, DURec, USB2, got much from UFX II, even the excellend preamps with 75dB gain)
- UFX II (Autoset, DURec, USB2, 30ch interface)
- UFX+  (Autoset, DURec, USB3/2/TB, MADI)

I leave out MADIface XT, it's a bit special and focuses more on the special case to offer 3 MADI busses (btw, had Mic/Line, but no Instr inputs).

BTW, as you can see in my Excel in Line 30 the converter latency of the BBF Pro FS is already excellent.
The RTL depending (mainly) on ASIO buffersize is also excellent for each of the devices as you can see in the screenshot.
So for you there is no reason to switch to another recording interface, the little differences in converter latency are marginal.