Solved one problem but now I have a new one :(

Sound card timing

I replaced my AMD k6 with a Cyrix of the same speed (300mhz) since someone mentioned that the AMD processor is known to have probs with audio. Upgraded my memory from 32mb to 56mb even though 32mb was still plenty for ntrack.
Gave windows 98 a clean install, disabled EVERYTHING on startup except the core system components. I even disabled the startbar clock, disabled cacheing of drives and all the other tips from music recording tip sites.
Now NTrack works correctly! (almost) :)

I still have a problem that may have been part of my old problem as well…
Everything is working in ntrack, I can get upto 8 stereo tracks with no problems except that playback timing is just a little off from the recording no matter how many tracks.
It’s not even ntracks problem.
I’ve used other software that lets me monitor my sound card input through live processing (full duplex) and they all have the problem.

The problem is, notes will play just a few cents off tune once it gets lively processed. I can hit a C on my piano through ntrack using LIVE button and while listening to it on the piano itself compared to the computers live output there is a slight difference in pitch. It is very slight, like only a few cents off.
This really becomes noticable when overdubbing/adding new tracks because it gets the timing all messed up with even only two tracks.
The sampling rate makes a difference also- 44.1 makes it sound a few cents up from C note, whereas 22 or 16khz makes it sound a few cents down from C while hitting the C on my piano for reference.

Could this be the sound card itself? It has a crystal clock on it, but even a few other decent sound cards I have have this same problem.
My motherboard has built in audiopro sound chip that I have disabled through the bios settings, but even when I use it just to see if it may work better than my nice sound cards, even it has this problem.
So are all my sound cards just crappy, or is it Win98 that has the timing problem, or is it directly from my motherboard?
I just don’t get why it’s doing this.
Please help, I really REALLY want to be making music, not toying with this crap for what feels like the rest of my life! :O

Motherboard- TX Pro 2 (also known as m571 v7.0)
SIS 5598 onboard video
32mb dimm and 24mb simm installed for total of 56mb ram.
Built in soundpro 8738PCI (disabled through bios so I can use my own)

Harddrive- Quantum lightning 7.5gb ultra ata 2
NTrack v2.3 (not that this matters, all the software have the problem)
Windows 98 (basic)

Soundcard- I’ve now tried maestro 1 pci, Aztech washington 16 ISA, Vibra 16 (SB16), and the built in soundpro chip.
I can’t use my turtle beach because it’s not supported for win98, so I dunno if this would have worked.
I have never had more than one sound card installed at once.

Also, before someone asks me…
I’ve tried checking and unchecking the “Use System Timer For…” in prefrences and didn’t help any.