Driver problem i think

I have a Compaq Presario notebook with windows xp pro. I bought a PCMCIA to USB 2.0 card with an external 16 x dl benq DVD burner. I inserted the card drivers installed fine, plugged in burner drivers installed fine. When I checked in my device manager all my driver said they were working properly, but when I try to burn a DVD with Nero 6.6.06 or any other software it only burns at like 1x. The funny thing is if I start a program at the same time I am burning to jump my CPU level up to 100% then it burns fast. It seems like if my CPU is at 50% it burns at 4x if my CPU level is 100% it will burn at 8X. I tried the same card and same burner in a different notebook with same OS. It installed the driver on its own and worked fine. I updated my bios and reinstalled OS this makes know sense to anybody I asked about this issue. Any help would be great.

I believe it may be due to you using an adapter, and also that PCMCIA is not as fast as it needs to be to compete with USB 2.0 To really know, Id like to see the model number on your Presario.

That is a Presario 2100 Athlon AMD