This is anecdotal, but I have an old Peavey PV-6 USB interface on an older Core 2 Duo laptop running Linux and a program called Guitarix through Jack interface software and I am able to get 4ms. It is not without the occasional click but I'm not using it for recording only live playing. I do not have any noticeable delay.
I use the PV-6 to send the audio from my guitar into my laptop, then from my laptop back to the PV-6 and then out to my amp. Using the laptop into the PV-6 and then using the line out built into the laptop did not work very well, having everything on one device really cut down the latency and glitches. Is your interface handling both the input and the output, or just the input?
One of the keys I found with this particular software was using settings that equaled out to a whole number like 4ms or 8ms and not 11.1. My USB interface didn't like it.
I use a Sample Rate of 96000, Frames per Period of 128, Periods per Buffer of 3. Maybe your software has something similar?
Or try out some Linux software based around a low latency kernel and the JACK interface software.
/r/linuxaudio and http://www.bandshed.net/avlinux/ if you're interested in checking out. All free software.
Also http://rakarrack.sourceforge.net/ https://guitarix.org/
I'm on Linux, but jack2 and either guitarix or rakarrack work great for me. The flow I use works great for recording aswell.
Rakarrack as well as Jack are available for other platforms.
Using Ultrawave Guitar Racks http://www.ultrawavestudios.co.uk
It's great for effects and even recording .wav in real time. My setup has less than 10 ms delay.
However my primary setup is still jackd audio server with rakarrak on Xubuntu. Better timings there.
EDIT: If you're longing for making your computer work like a distortion pedal with minimal delay - JUST GET LINUX (Ubuntu/Xubuntu/Fedora/Anything). Install qjackctl, rakarrak, guitarix, and lingot or gxtuner for tuning the guitar.
My latency is 1.33ms, and I'm doing this through a shitty laptop. Bottom line is Linux gets you more oomph per cycle.
When you say all-digital, are you looking for the guitar to be synthesized, or do you just want the amp done digitally?
The former I can't help with, but the latter I can. Rakarrack is one of the few VSTs that work well, and it's free on top of that.
It doesn't have as nice of a sound as many of the other VSTs for Windows, especially the paid ones, but if you can splurge some money, some of them work well in WINE if you take your time to set up wineasio. I've been running both Guitar Rig 3 and 4 through WINE with the use of JACK, and it runs well enough that I never booted into Windows.
Alternatively, does your amp not have a line-out jack? Most of the higher end amps do, and even if you don't, you should be able to use a DI box for it (but that's not something I've touched before.. at all). That way you can just use an input without having to use a VST.
Cheapest: $7 + headaches (optional)
Buy a Radio Shack 1/4" to 1/8" adapter to plug your guitar into the microphone jack on your computer
Install Linux
Get Rakarrack a free guitar multi-effects processor
Possibly Troubleshoot Sound Card issues
http://rakarrack.sourceforge.net/
Hello u/Ingredients_Unknown, it appears you tried to put a link in a title, since most users cant click these I have placed it here for you
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This is a great question! I don't really know the answer for this.
There are two devices shown for Guitarix. One is the amp head, the other is the FX. See the screenshot below of the default routing.
I tried bypassing the head and routing to the FX block only. However, when I did this, I didn't get any signal. This may work for you if your incoming signal is Line instead of instrument level going into the block. I don't currently have the proper equipment to test that now.
Another option if you are just looking for FX is Rakarrack
That is more focused toward guitar FX than emulating a tone stack of an actual amplifier.