WD Hard drive help

[XRWKEN]

I have 2, I7-920 rigs, both are identical except for the hard drives

One has the WD raptor WD1500ADFD 150 gig and the other is
WD Black WD6401AALS 640 gig

The 640 gig black hd is getting 88mb/sec speed but my 150 gig raptor is only geting 52mb/sec speed.

it has always been my understanding that the Raptor hard drives are the Fastest hd's
Both hd's have write-caching enabled
Does it have anything to do with the fact that the raptor drive has 98 gigs of free space and the black 640 gig hd has 556 gigs free

What gives here?
tx
Ken

 

[roadrunner197069]

The 150G raptors are old tech with slow transfers by todays standard, and that new 640 black gives a velociraptor a run for its money.

I had 2 WD blue in raid 0 on my i7 and was getting 180mb/s, now i got 4 30G ocz core v2 in raid 0, @ 507mb/s.

Fast drives rule, ditch the raptor and get another WD 640, or even more then one for raid 0.


i7 loves fast drives.

 

[pjmelect]

Although I can’t comment on the relative merits of the WD Raptor WD1500ADFD 150 gig and the WD Black WD6401AALS 640 gig it is true that the transfer speed of a hard disk is much faster at the beginning of the disk than at the end of the disk perhaps by as much a factor of two which is why defragmenting programs move the most commonly used programs to the beginning of the disk. Also how fragmented is the Raptor drive. To get any meaningful comparisons between the two disks the benchmarks should be performed on empty drives.

 

[MRFS]

In order to maintain the same or similar recording density,
the rate of bits being written by the READ/WRITE heads
slows down in proportion to the velocity of the track
directly beneath it.

Thus, at the outer tracks, the bit rate is highest;
at the inner tracks, the bit rate is lowest.

The circumference of a circle equals PI x diameter;
as a track's diameter decreases, the total length of that
track decreases.

PI (pronounced "pie") ~= 3.14159

At a constant number of revolutions per minute ("rpm")
and at a constant recording density, more bits pass
under the READ/WRITE heads during one revolution
of the outermost track than pass under those heads
during one revolution of the innermost track.

And, when a hard drive is empty, an OS will begin writing
the outermost tracks first.


Summary: modern hard drives transfer data the fastest
when they are empty.


Now, before trying to diagnose the 2 measurements you have shared,
WHAT SOFTWARE DID THOSE MEASUREMENTS?

p.s. try other programs to see if you get the same difference


MRFS

 

[XRWKEN]

I was using pc pit stop for the above results, come to find out that pc pit stop sucks, anyways I got hd tune and ran it on both hd's. The 640 gig blk edition still did better. What I want is a very fast HD for fps gaming, If my raptor is no longer cutting the mustard, then so be it, I will get one that is better, but what one to get im not sure. the 640 gig hd that im using in my other rig or something even faster then that one?

Thoughts?comments? tx
Ken
click on pic to enlarge

640 gig black ed.

150 gig raptor

 

[turboflame]

That looks about right. The 640GB uses platters with a higher data density (320GB each). Raptors are still good for their lower access times but when it comes to transfer rates the larger HDDs can't be beat.

 

[jitpublisher]

The faster access of time of the Raptor should make it "feel" faster.
For gaming, IMHO, faster access time is better for performance than higher sustained transfer rates. When the game first loads, probably the 640 gig drive is going to give you better load times as it loads all the information into memory.
But as you are playing along in the game, as the game needs to access info from the drive, the fast access time is going to help more.
We are not talking about big differences here. But generally, the fast access time will benefit most people more than the higher sustained throughput, unless you spend a lot of time moving big files around.
But there is no debate, some of the new in-expensive drives have nearly caught up to the Raptors in overall performance. And if that 640 gig drive was spinning at 10K like the Raptor, it would likely match it, even maybe beat it, in access time.
The Raptors are enterprise class drives though, and the average lifespan of a Raptor is double that of non-enterprise drives. (on paper anyway)

 

[MRFS]

You must factor in the predictable effects of Perpendicular Magnetic Recording:

remember the small pocket compasses we got in cereal boxes,
when we were kids? (Maybe I'm dating myself here

The compass needle aligns horizontally with the magnetic North Pole.

Just flip that needle 90 degrees, so it's pointing straight UP.

That's a good analogy for PMR = much higher recording density.


p.s. I just checked WD's website, and it does NOT mention PMR
in the VelociRaptor's specifications:

http://www.wdc.com/en/products/products.asp?driveid=499&language=en
http://www.wdc.com/en/products/products.asp?driveid=494&language=en


Compare the WD 1TB RE3 model:

http://www.wdc.com/en/products/products.asp?driveid=503&language=en

Perpendicular Magnetic Recording (PMR) - WD RE3 drives utilize PMR technology to achieve even greater areal density, reliability, and design margin.

[end excerpt]


MRFS

 

[XRWKEN]

Well I have decided I should and will replace my old gen1 raptor.
As what as what to replace it with is my unknown

A $200 300 gig velcoraptor
A $79. 640 gig black ed WD
2x $79 640 gig black ed WD in raid
A $69 500 gig blacd ed WD? Is a wd black ed, 500 gig hd going to be faster then a 640 gig? if not 640 gig will be better
2x $69 500 gig black ed WD in raid (if 500 gig hds are faster then 640 hds)

It would be nice if there was a direct comparison that had it in black and white,
IE:
this drive is the fastest for gaming and how much faster then the runner up( to figure out if its worth the extra money, If the velcoraptor is only like 1-2% real world noticeable faster it would not be worth the xtra $)