By the way, nice double strike from me and you
MoJo is pissed off now for sure
"Atmosphere is electric here in the SPCR Silencers Stadium. A Friendly match but a local derby too. Colleagues from the SPCR community are pitted against each other today. There's a buzz around the stands. PSUs are making a lot of noise back there in the terraces. Loud fans from FC OC are outside wanting to make a racket. SPCR Security will want to stop them from entering... there could be trouble. Hard drives are keeping calm and quiet however. You would barely know they're there. We've had a new generation who've made their way to SPCR Stadium amidst all kinds of adversities. Samsung F2 Ecogreen HD502HI being one. Let's hope it's a sign of things to come."
"So the goal here at SPCR is silence. And let's hope there's lots of them today. Both sides have had good use of the ball so far. But, all of a sudden, MoJo's lost possession cheaply. He almost gave it away. The space has opened up for the home team. LodeHacker and Thomas counter MoJo with a lightning fast two-pronged attack from both wings. His defence is floundering! Thomas with a superb cross... Shamgar arriving in the 18 yard box from midfield... volleys into the top right corner! What a strike! It's 1-0 and we've played less than 5 minutes!"
Sweet! Very creative, my hat's off to you.
Back to Random Access, please note my earlier post -- w/ AAM off on both drives, a WD640 (7200rpm) might be 2-2.5ms faster than the EcoGreen 500gb, but with AAM on, the difference is smaller, likely less than 1ms.Storage Review says
Access time is the metric that represents the composite of all the other specifications reflecting random performance positioning in the hard disk. As such, it is the best figure for assessing overall positioning performance, and you'd expect it to be the specification most used by hard disk manufacturers and enthusiasts alike. Depending on your level of cynicism then, you will either be very surprised, or not surprised much at all, to learn that it is rarely even discussed. Ironically, in the world of CD-ROMs and other optical storage it is the figure that is universally used for comparing positioning speed. I am really not sure why this discrepancy exists.
Perhaps the problem is that access time is really a derived figure, comprised of the other positioning performance specifications. The most common definition is:
Access Time = Command Overhead Time + Seek Time + Settle Time + Latency
Unfortunately, this definition is not universal, and is made complicated by the fact that manufacturers refuse to standardize on even what access time's subcomponents mean. Some companies incorporate settle time into seek time, some don't, for example. And to make matters worse, some companies use the term "access time" to mean "seek time"! They really are not the same thing at all.
In the end though, when you are looking at the ability of a drive to randomly position, access time is the number you want to look at. Since command overhead and settle time are both relatively small and relatively similar between drives, that leaves the sum of seek time and latency as the defining characteristic between drives. Seek time and latency are a result of very different drive performance factors--seek time being primarily a matter of the actuator and latency the spindle motor--resulting in the possibility of some drives being better in one area and worse in another. In practice, high-end drives with faster spindles usually have better seek times as well since these drives are targeted to a performance-sensitive market that wouldn't buy a drive with slow seek time.
Let's compare a high-end, mainstream IDE/ATA drive, the Maxtor DiamondMax Plus 40, to a high-end, mainstream SCSI drive, the IBM Ultrastar 72ZX. (When I say "high end" I mean that the drives are good performers, but neither drive is the fastest in its interface class at the time I write this.) The Maxtor is a 7200 RPM drive with a seek time spec of "< 9.0 ms", which to me means 9 ms. Its sum of its seek time and latency is about 13.2 ms. The IBM is a 10,000 RPM drive with a seek time spec of 5.3 ms. It's sum of seek time and latency is about 8.3 ms. This difference of 5 ms represents an enormous performance difference between these two drives, one that would be readily apparent to any serious user of the two drives.
As you can see, the Cheetah beats the DiamondMax on both scores, seek time and latency. When comparing drives of a given class, say, IDE/ATA 7200 RPM drives, they will all have the same latency, which means, of course that the only number to differentiate them is seek time. Comparing the Maxtor above to say, the Seagate Barracuda ATA II with its 8.2 ms seek time shows a difference of 0.8 ms, or around 10%. But the proper comparison includes the other components of access time. So the theoretical access time of the Maxtor drive is about 13.7 ms (including 0.5 ms for command overhead) and that of the Seagate Barracuda drive 12.9. The difference now is about 6%. Is that significant? Only you can judge, but you also have to remember that even access time is only one portion of the overall performance picture.
Remember that access time is an average figure, comprised of other averages. In fact, access time on any particular read or write can vary greatly.
It is important to remember that access time and transfer rate measurements are mostly diagnostic in nature and not really measurements of "performance" per se. Assessing these two specs is quite similar to running a processor "benchmark" that confirms "yes, this processor really runs at 2.4 GHz and really does feature a 400 MHz FSB." Many additional factors combine to yield aggregate high-level hard disk performance above and beyond these two easily measured yet largely irrelevant metrics. In the end, drives, like all other PC components, should be evaluated via application-level performance.
It's instructive to read SR's review of the Hitachi Deskstar 7k1000
(a 7200rpm 1tb drive) which is extensively compared against the then speed king the WD Raptor 1500. The latter had a 2ms speed advantage but much lower areal density. In many of SR's extensive performance testing, the Hitachi came out ahead and in the end, "displaces WD's Raptor WD1500ADFD as the fastest drive around when it comes to single-user performance."
With that info as the backdrop, I doubt very much that a real user at a typical desktop could tell the difference between the Samsung EcoGreen 500gb and the WD640 as OS drives.
There's no question that multiple drives are needed for very high performance in Photoshop -- at min, a scratch drive. I recently built a custom high end Photoshop workstation for an old client -- i7-920, 12gb ram, Intel x80-m ssd, and TWO Raptor 1500s for scratch discs from the system I built him some 5 years ago.