I'm not entirely sure if there was a question for me in your last post, but there were a few things that didn't sound quite right, so I'll try to respond to that:
AFAIK, Windows Media Player doesn't come with its own drivers. It's a media-playback application. A driver is "hardware-support" software that makes the connection and handles the audio streams between the operating system (i.e. Windows 7 in your case) the audio software (in this use-case Windows Media Player) and the hardware (in your case, the R8).
So, when you say that you tried to get rid of the "WMP Driver", I don't know what you mean.
If you mean the WDM (not WMP) driver - don't get rid of it. Windows needs that, and even ASIO4All needs that to be present to do it's job.
The point was just not to use a playback app that doesn't allow you to select an ASIO driver. So, instead of Windows Media Player, maybe use something like Audacity and make sure that the ASIO driver that comes with the Fast Track Ultra 8R (it DOES come with such a driver) or at least ASIO4All (which is a "workaround" for audio devices that don't have such a driver, that shouldn't be necessary for the Fast Track Ultra 8R interface), is selected in that application (e.g. Audacity).
To keep it more to the point:
1. Avoid Windows Media Player or any audio playback app that doesn't allow you to choose an ASIO driver on Windows
2. If you have an audio interface that has its own ASIO driver available, use that. No need to use ASIO4All in that case - but DO use the ASIO driver that was made for the interface (visit M-Audio.com to download the latest available driver for your operating system, then download and install it).
3. Only if you do NOT have an audio interface that has it's own ASIO driver, then download and install ASIO4All. ASIO4All is a 'workaround' for poorly performing WDM/MME/WASAPI drivers - most commonly for "built-in" type of audio interfaces on laptops or desktops. If a "native" ASIO driver is available for an audio interface you added/connected to your computer, 99.9% of the time, it will work waaaaaaaaaaaaaaaaay better than ASIO4All (...or WDM/MME/WASAPI for that matter).
So, if, for example, you're on the go and connect your headphones straight to your laptop (and do NOT have the 8R connected), then it makes sense to use ASIO4All with the laptop's built-in audio interface and playback software that supports ASIO (e.g. Audacity or any DAW). This should give you better latency than when using the built-in audio interface with Windows' own WDM/MME/WASAPI drivers.
(However, if you DO have your 8R connected, do NOT use ASIO4All, but use the M-Audio ASIO driver instead, since that'll give you even better latency and not cause any potential issues as ASIO4All sometimes does, as it's just a workaround).
As for using your Arturia softsynths... it's the same thing:
WME/MME/WASAPI: Terrible latency
M-Audio ASIO Driver: Should be pretty good... set the buffer size as low as you can before it starts crackling. You should get the latency down to around 8-12 ms with a softsynth and that interface. At 8-10 milliseconds, most people can't even tell there's latency. (And softsynth latency is comparably "faster" since it only goes "one way". The sound gets generated in the computer, and only goes "one-way" out of the computer. So, only one time the 8-10 ms. If you want to record an external audio source, then there's TWO audio buffers at play... one on the way into the computer, and another one the way out. And they add up. So, if you were to record something with a microphone and want to software-monitor it via an application that uses ASIO, you have nearly double the latency to deal with, than when playing a softsynth, where the sound is generated in the computer and "only" goes to the output (nothing comes in on the input). So, one buffer instead of two means, that the softsynth latency shouldn't be so bad... around half that of when recording external audio and monitoring it back via software-monitoring).
ASIO4All: If you're lucky, you can get similar latency values out of ASIO4All as with the M-Audio ASIO driver... but it might not work quite as smooth, so maybe you'll get 10-15 ms latency out of it, instead. Most people start noticing that there's a tiny bit of latency once it's above around 12 ms - especially when playing something percussive like MIDI drums. For playing keyboard lines, you probably still won't notice any latency.
So, if you get too much latency/delays when playing your Arturia synths, you're either using the wrong driver (WDM/MME/WASAPI), or you're using ASIO4All and it doesn't work very well with your setup, or you'r using the proper M-Audio ASIO driver for your M-Audio audio interface, but the buffer size is set much too high (if so, lower it and try again).
And just because you said "MIDI latency" - the latency doesn't come from MIDI. MIDI itself is very fast, and you won't notice the latency of MIDI itself. The latency is all related to the computer having to process/generate the sound and for that, the audio buffer needs to be set to the smallest value possible before there's dropouts/crackling (i.e. when there's not enough time/buffer for the computer to complete it's calculations) - that will give you the best possible latency on your computer.
So much for the general terms where "software" ends, "drivers" begin and what they're for (bridge between software and hardware), and how important "buffers" are for latency.
If I understand better what the actual question is, then maybe it would help to look at the song you're testing this with... but at this point, I'm not completely sure. Besides, if it's a problem with buffer sizes or selected drivers, then the situation is dependent on the computer that is being used and the settings that have been made... so, if you'd share a song and I'd load it here, I probably wouldn't even have the same issue on my end.
Anyway... I hope what I wrote here helps a little to get your head around computer-audio, different driver types and the importance of the size of the audio buffer for latency.
Cheers
