Hi, running Athlon64+ 3000, 2.5GB RAM. XP

Using my SATA HD for cache as it was giving read  speeds 4x my Sandisk 4GB Card (SDR113 USB). About 40MB/sec.  The card was only giving me 10MB/sec.

I noticed my cache fill % dropping and the read speeds getting real low.   Now it’s under 10MB/sec, Cache fill is 15%. Do I have a problem?