Spread Spectrum Clocking enabled = faster?

[whitman]

In my hack pro, built with a GA-EP43-DS3L the only drives that work well are either brand new Western Digital drives or Western Digital drives in general that have the jumper to enable SSC (Spread Spectrum Clocking.) I've tried Seagate 7200.7 7200.9 7200.10s, two Maxtors, a WD Raptor and three different WD Caviars ranging from 4yrs old to brand new. The older WD drives have a jumper in the back for enabling SSC on the drive, all of the other brands don't have the option.

 

The thing is, with the same exact disk image on every one of the drives, when SSC is enabled (on the older WD drives) the bootup time is lightning fast and QUIET. Seriously, it stays on the apple logo for maybe five or six seconds then nearly instantly it's on the desktop and done loading, not even a peep from the HDD.

 

When SSC is disabled on the drives (or if I'm using any of the other brands that don't have the option) it is LOUD and slow. It will take nearly 35 seconds on the apple logo, grinding away and once it makes it to the desktop it still has a couple of seconds of loading to do. The sound difference and speed difference is fully noticeable on the WD drives when I test them SSC enabled and SSC disabled.

 

A note to make here is that a brand new WD Caviar drive (doesn't have a jumper for SSC) runs lightning fast as well, while the other brands perform slow and loud. I wouldn't have noticed the difference and would have just lived with it, but I purchased the new WD drive and the difference was amazing. Through thorough testing, I narrowed it down to WD drives and SSC being enabled.

 

Does anyone have an idea why this is happening?

 

whitman

 

Edit: http://www.seagate.com/www/en-us/support/d..._Toggle_Utility

 

Found the SSC toggle utility for Seagate drives, will give it a shot tonight. If SSC makes as much of a difference as it does on the WD drives, the end is near.

 

whitman

[whitman]

enabling SSC made a difference on a 7200.10 but not the 7200.9.

[ryan200]

spread spectrum is meant to reduce the amount of emi produced.

 

something in your rig must not be shielded well against the emi your hard drive is putting off.

 

perhaps unrelated but i noticed with the same motherboard seems to have more dpc latency than other computers i have had. i found if i disabled the cpu eist function in the bios it helped with the spikes.

 

the reason i bring it up is i wonder if you disable cpu eist function in bios and you disable spread specturm on the drive if it would produce the same lightning quick results.