slower access after putting in new faster hd? why?

[takeru]

before i had these two hd's on the same ide cable:
ibm 46gig 7200rpm ata66 : cache speed 36.5meg/s
wd 120gig 7200rpm ata100: cache speed 47.1meg/s (8meg cache)

then i swapped the 46gig out, so now it's:
wd 120gig 7200rpm ata100: cache speed 36.4meg/s (8meg cache)
wd 120gig 7200rpm ata100: cache speed 15.3meg/s (8meg cache)

ibm 46gig 7200rpm ata66 : cache speed 36.1meg/s (on another cable now)

after running cache speed test several more times, the second 120gig hd averaged around 30.5meg/s. wtf? how can putting in a second faster drive slow everything down that much? am i missing something here? i am running windows 2000.

 

[mboy]

Bigger drive is slower then smaller drive.

 

[bacillus]

is dma enabled for that "slow" hdd??

 

[Dundain]

Um, just a question to begin with...what IBM drive comes in at 46Gb? Thats not exactly an, ahem, standard size. Secondly, what program are you using to get these measurements from? Are you measuring just the cache speed? Or actual transfer rates? There's alot of variables that can show the drives at far different speeds from what they're actually capable of. What IDE driver are you using? Is UDMA actually enabled for all the drives?

 

[ojai00]

Make sure DMA is enabled and that you have it on the right channel (primary ATA100). Make sure that your jumpers are correct.