TV is slow

[kknull]

TV-Server Version: none
MediaPortal Version: RC2
MediaPortal Skin: blueskin
Windows Version: XP mce 2005
CPU Type: athlon 64 4800+ X2
HDD: 500GB
Memory: 1Gb
Motherboard: Asus M2A-VM-HDMI
Video Card: Radeon X1200 (integrated)
Video Card Driver: catalyst
Sound Card: Realtek HD Audio
Sound Card AC3:
Sound Card Driver:
1. TV Card: Hauppauge 878 wintv-express
1. TV Card Type: analog, software encoder
1. TV Card Driver:
2. TV Card:
2. TV Card Type:
2. TV Card Driver:
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:
MPEG2 Audio Codec:
h.264 Video Codec:
Satelite/CableTV Provider:
HTPC Case:
Cooling:
Power Supply:
Remote:
TV:
TV - HTPC Connection:

Hi,
it seems that tv on mediaportal runs slowly, it's not fluid, both in playback and recording.
If I use the program supplied with the card (wintv2000) it is normal.
May I have to choose a different video encoder in mediaportal?

P.S. I do not use the Tv server, I didn't manage to make it work correctly..

Thanks.
KKnull