Something's limiting my HD speed.

[Calumus]

Hey, I just did a little upgrade to my system and its not performing like it should. With my old set up I was running 2 15k rpm sas drives in raid 0. I was averaging around 145MB/s in both hdtach and hdtune. I swapped them out for a new Seagate cheetah 15k7 300Mb drive. I've seen several tests of these drives online and all put their average speed between 190-200MB/s. I'm using the same raid card, on the same mobo. I did a fresh install of Win 7 ultimate, and updated the bios of the card. Now, in both hdtach and hdtune my read is a flatline from the beginning to the end of the drive, in hdtune its 110, hdtach says 120MB/s. I know I'm limited to whatever pci express 1x can handle; but I shouldn't have slowed down at all. Other then the drive, the only difference I can think of is that I'm now running security essentials instead of avira. I've disabled it, but it makes no difference. Anyone have any ideas? I'm stumped.

 

[Emulex]

did you disable write cache on the drive itself? or is this a read-only problem?

a poor sas/sata cable could cause the driver to downgrade speed - check your s.m.a.r.t to see if you are getting cable ecc errors. it would step down speed rather than crater your storage.

 

[Calumus]

Hey, thanks for your suggestions. Sorry it took so long to get back here, busy month. I swapped out the cable and get the exact same results. The raid card is a promise fast trak 2650. According to the management software write through caching is enabled on the card, and write caching is enabled on the drive. s.m.a.r.t. says everything is fine. So I'm still at a loss as to what the actual issue is. I'd appreciate any other ideas that anyone might have. Thanks.

 

[Shmee]

is there a jumper on the drive that might limit it to SATA one speeds? Some HDD's have this, though I know this is an enterprise drive using SAS, it is worth a check

 

[Old Hippie]

is there a jumper on the drive that might limit it to SATA one speeds?

SATA1 is 150MB/s he's doing 110MB/s.