i have now had the time to check where the problem lies. graphics board or motherboard. It's the motherboard. The board i checked back with is i915p-based (my mums pc).
That means: modbin's installer works like a charm with the PCIe-Version of the X1650Pro Card (in my case manufactured by MSI).
The problem seems to lie in the VIA-based mainboard...
You can renamen the thread to x1650agp/pcie.
Will now have to find the problem with the VIA-chipset PCIe!?
Or could it be the TFT-Screen? (I connected it with the same DVI-to-VGA-connector that i used on the other pc with it's CRT).
Edit: I took the working CRT-monitor over to my desk and hooked it up to my pc (see signature). Ran the x1650-installer. Rebooted and it worked. Then i took away the CRT and put on the TFT (with the running system) and it recognized the monitor-resolutions (a lot less than the CRT offers). Perfect.
Then i rebootet with the TFT-monitor connected. Back to my picture with only colourful stripes. Seems that my monitor is not appreciated on start...
Tried already another TFT-monitor. Didn't help it.
Sorry for spamming the thread more or less. But i'm hunting the solution. Seems to be out of reach for me. Perhaps somebody else will find my results helpful (for not having to find out everything by himself).
-Edit the following values of ATIinject.kexts Info.plist:
<integer>0x71c5</integer> <---this is for X1600 edit to mach yours!
<integer>0x100</integer> <--- Size of VRAM, here 256MB (512MB is 0x200; 128MB is 0x80; 64MB 0x40;) You can also try to remove this entry!
<integer>0x00000080</integer> <--- edit this to half of the value above (if card is 512MB set it to 0x100)
<integer>0x00300000</integer> <--- don't know about that! try and play! You can also try to remove this entry!
now remove ATINDRV.kext and insert ideneb v1.4 install dvd open it with pacifist look for X1900 then just copy ATINDRV.kext from there to your /system/Library/Extensions run diskutility to repair Extensions it got CI/QE running