Weird harddrive performance after installing on MSI-6195

Gentlemen. I love my new WD 30 gig 7200 rpm harddrive. It's noticeably faster than the old Maxtor 10 Gig 7200 rpm that it replaced. The WD gets a flat 26 Meg/sec. on HDTach. Whereas the old Maxtor only got 20 Meg/sec peak.

Although I'm happy with the boost in horsepower, things are now looking really weird on my secondary controller.

My primary EIDE controller has only the WD 30 gig as a Single Master.

My secondary controller has a Quantum Fireball 6.4 Gig as a Secondary Master to a Samsung 8/8/32 cdrw burner (Slave).

With my old 10 Gig Maxtor HD installed as the primary single drive on the primary controller, I would see about 12 Meg/sec peak throughput on the Quantum drive on the secondary controller. It would also us about 2 % of my cpu utilization.

However, with the new 30 Gig WD all alone on the primary controller, my secondary controller has slowed down to a crawl. It benchmarks with a flat 3 Meg per/sec with a 99% cpu utilization.

I switched out the Quantum for a similar 6'ish Gig 5400 rpm Maxtor drive that I have laying around. This Maxtor also used to bench at about 12 Meg/sec peak throughput. However, with the new WD installed on the primary controller, even this Maxtor was showing the same 3 Meg/sec with 99% cpu utilization when installed on the secondary controller.

I'm using the AMD EIDE driver for the irongate chipset. Is this a known problem with the AMD 750 chipset EIDE driver?

I've read that I should only use the AGP driver for the AMD-750 chipset, and let win'98 SE install her own native drivers for everything else.

Note that I didn't perform a fresh OS install with the harddrive upgrade. I'm really lazy, nuff said.

Thanks for any info.

-Brian

BTW, things run a lot zippy during boot and program startup. I just don't like seeing my secondary controller run like crap now.