tvserver without running mediaportal client results in stuttering on other clients (1 Viewer)

[McHep]

TV-Server Version: 04-06-2007--01-22h--Rev13861
MediaPortal Version: svn--04-06-2007--01-01-Rev13860
MediaPortal Skin: BlueTwo
Windows Version: Windows XP MediaCenter with SP2 und Rollup 2
CPU Type: Pentium 4 - 3 GHz
HDD: 2 Samsung HD160JJ
Memory: 1,5 GByte
Motherboard: ASUS
Motherboard Chipset:
Motherboard Bios:
Video Card: NVidia FX5900ZT
Video Card Driver: 6.14.10.9371 - 22.10.2006
Sound Card: Creative SB Audigy 2 ZS
Sound Card AC3:
Sound Card Driver: 5.12.4.1196 - 11.08.2006
1. TV Card: Cinergy Hybrid T USB XS
1. TV Card Type: DVB-T
1. TV Card Driver: 4.6.206.0 - 06.02.2006
2. TV Card: Cinergy T USB XS
2. TV Card Type: DVB-T
2. TV Card Driver: 4.6.206.0 - 06.02.2006
3. TV Card:
3. TV Card Type:
3. TV Card Driver:
4. TV Card:
4. TV Card Type:
4. TV Card Driver:
MPEG2 Video Codec: NVIDIA PureVideo Decoder 1.02-196
MPEG2 Audio Codec: NVIDIA PureVideo Decoder 1.02-196
Satelite/CableTV Provider: IESY
HTPC Case:
Cooling:
Power Supply:
Remote:
TV:
TV - HTPC Connection:

If I'm running tvserver without running also the mediaportal client on the same computer the tvclient on other client are stuttering. When I then starting the client on the tvserver the tvclient on the other client have no problems with streaming.