The RPM Factor

RPM, or revolutions per minute, is the measure of instances that the motor of the hard drive can rotate the platters by a full 360 degrees. Currently, there are various drives from a few different manufacturers that can rotate their platters 10,000 to 15,000 times per minute, or 15,000RPM. The most common drives today are rated at 7200RPM like our 400GB 7200.8 Seagate Barracuda, and there are still many 5400RPM drives around also.

So, does the speed of a drive's motor really make a difference in the performance of a drive? If we look at just the speed of the motor, then yes, there is a great performance boost from a 7200RPM drive to a 10,000 or 15,000RPM drive. The faster that the motor can rotate the platters, the quicker that the read and write heads can do their job on the platters. But there are other factors that come into play when measuring the performance of a hard disk drive. SATA based drives have a maximum data transfer rate of 150MBs/sec (megabytes per second) while IDE drives top out at 133MBs/sec. The transfer rate can be enough to even things out under certain circumstances. The same goes for the amount of cache on the drive. A 7200RPM drive with 16MB of cache has been proven to compete with a 10,000RPM drive with 8MB of cache, again, in certain situations.

We have taken two of the latest drives from Maxtor that we could get our hands on to compare the differences in performance between the DiamondMax 16 series 160GB drive with a 5400RPM motor, and the DiamondMax Plus 9 series 160GB unit with a 7200RPM motor. Both drives are of the PATA/133 flavor, have 8MB buffers on board, and have a total of two 80GB platters each. With the physical specifications being identical in every aspect, let's take a look at how the two units compare in performance based on their spindle speed.

5400RPM vs 7200RPM Spindle Speed
DiamondMax
Plus 9
(7200RPM)
DiamondMax 16
(5400RPM)
7200RPM Performance Advantage
SYSMark 2004 - Internet Content Creation Performance
Overall
195
191
2.09%
3D Content Creation
174
172
1.16%
2D Content Creation
251
244
2.87%
Web Publication
170
167
1.8%
SYSMark 2004 - Office Productivity - Communication Performance
Overall
153
144
6.25%
Communication
144
122
18.03%
SYSMark 2004 - Overall System Performance
Overall Performance
173
166
4.22%
Internet Content Creation
195
191
2.09%
Office Productivity
153
144
6.25%
Winstone 2004 - Overall System Performance
Business
25.5

25

2%
Multimedia Content Creation

31.5

31.5
0
Pure Hard Disk Performance - IPEAK, Winstone 2004
Business
442
383
15.4%
Multimedia Content Creation
267
238
12.18%
Real World Performance - File System Tasks (seconds)
File Zip (1 300MB File)
61.331
74.224
21.02%
File Zip (300 1MB Files)
62.811
72.594
15.58%
File UnZip (1 300MB File)
14.383
15.500
7.77%
File UnZip (300 1MB Files)
14.857
20.021
34.76%
Copy Folder (1 300MB File)
5.765
8.216
42.52%
Copy Folder (300 1MB Files)
8.078
11.443
41.66%
Real World Performance - Application Load Times (seconds)
Photoshop CS
8.263
9.269
12.17%
Office 2003 - Word
1.984
3.355
69.1%
Office 2003 - Excel
2.323
2.979
28.24%
Office 2003 - Access
1.662

3.816

29.6%
Office 2003 - PowerPoint
2.289
3.823
67%
Real World Performance - Game Level Loading Times (seconds)
Half-Life 2 (d1_canals_01)
23.867
21.2
-12.58%
Doom 3 (caverns1)
45.667
47.567
4.16%
C&C: Generals (GLA C3S1)*
34.300
34.867
1.65%
Service Time
IPEAK Average Read Service Time
13.82
23.31
8.13%
WinBench 99 - Transfer Rate Test
Beginning
59400
47200
25.85%
End
33800
26800
26.12%
*C&C:Generals playing as GLA (campaign 3, stage 1)

The greatest performance increases were seen with our Real World File System Tasks as well as Application Load Time tests. The 7200RPM unit picked up data off its platters much more quickly than the 5400RPM drive. There is no question that a drive's spindle speed has a great effect on the overall performance of the drive. There were certain situations where the spindle speed made no difference like the game level load times, for example. The 5400RPM drive loaded Half-Life 2's d1_canals_01 map more than 2 seconds quicker on average than the 7200RPM mode. Still, this is not a large enough margin to conclude that a higher RPM does not have a positive impact on a drives overall performance.

Seagate on NCQ Hard Drive Buffer: Does Size Really Matter?
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  • zforgetaboutit - Thursday, May 26, 2005 - link

    The review has a table showing the drives' spec sheets. Among the stats are "average seek times (AST)". But I don't see average seek times benchmarked, as such.

    So, on the one hand, the Seagate's spec shows an AST of 8.x seconds, but other reviews have shown it to be 11+ seconds.

    I propose that if the review goes as far as to publish the purported AST, then it has an obligation to test it as well, with a discrete benchmark, such as HDTach or some other explicit AST benchmark.

    Otherwise companies will start to claim 2 ms AST, and Anandtech won't be able to refute it, if it's a blatantly bogus claim.

    Reply
  • OrSin - Tuesday, April 26, 2005 - link

    I see you explain how you take your sound measurements, but you really need to do it differently. The raptors are load as hell and seagate are queit and accourding to measure they are equal? Serious I undestand your reasoning for it, but it's just flawed. If a test seems right but produces obviously (and I mean obviously) wrong results then you need a new method.

    I had to send a raptor back it was so loud. I had to look at my computer (SFF) evertime i booted up to make sure it was going to rock off the table. Now my computer was a not actually moving but it sounding like it vibrating enough to move.
    Reply
  • Zak - Monday, April 25, 2005 - link

    Your articles are often difficult to read due to your use of some weird convoluted sentence structure. Why can't you guys use simpler, more accessible language??? Exampple:

    "RPM, or revolutions per minute, is the measure of instances that the motor of the hard drive can rotate the platters by a full 360 degrees."

    How about:

    "RPM, or revolutions per minute, the speed of platter rotation: how many times the platters rotate every minute." or something like that.

    Zak
    Reply
  • JPSJPS - Monday, April 25, 2005 - link

    Purav Sanghani - Poster 32 and especially poster 33 pointed out an obvious mistake that only a complete newbie would make. This makes all of your data questionable!!! Have you considered having someone with a little technical knowledge review your stuff before you publish it? Reply
  • PuravSanghani - Friday, April 22, 2005 - link

    TrogdorJW: The recordings as well as decibel readings were taken 1" away from the side of each drive. Obviously the sound emitted from the drives would not be as loud when inside a sealed case, but to get an accurate reading of the sound emissions from each drive and comparing them to each other requires that we take readings close to each unit.

    smn198: You are right, the frequency of the sound produced by each drive does make a world of difference. In the past when looking at case fans, we observed that larger 120mm fans are quieter than smaller 80mm fans because they produce a lower frequency which is less noticeable to humans. This is definitely the case with anything that produces any sound, including hard drives.
    Reply
  • ohnnyj - Friday, April 22, 2005 - link

    I want to know how you get Photoshop to open in under seven seconds on a Raptor. My RAID0 array opens in about 14-15. It opens faster if you open, close, then reopen again so I wonder if this is how the test was performed. Reply
  • Phantronius - Friday, April 22, 2005 - link

    Just bought 2 160gig Barracuda's to replace my noisey as hell Western Digitals. I freaking love them, soooooo much quieter.

    Reply
  • TrogdorJW - Thursday, April 21, 2005 - link

    A few things to note on noise (from my perspective):

    1) The hard drive noise levels were probably taken very close to the drives in order to capture them. Just FYI. 52 to 54 dBA is rather loud. Purav, what was the distance of your SPL meter from the drives?

    2) Seek noise can be very noticeable. My own experience reflects what's in the charts, with the Samsung being the quietest. Seagate and Hitachi are moderately loud, and the Maxtor and Western Digital Raptor are the loudest. (Raptor seek noise sounds louder to me than what's in the recordings.) I don't know about the decibel ratings, but it seems like if you started the charts at 50 that it would reflect more what I hear. (i.e. Samsung would be 1.2 to 2.4 and Hitachi would be 1.6 to 4.4)

    3) Bearing noise is generally either near-silent (Samsung, Seagate, and just about any other FDB implementation, including the Raptors) or else it's noticeable. The WDxxxxBB/JB models are notorious for having a lot of bearing noise, as are older Maxtor drives. I've got four WD's at my place, and I hate them all! :-p (They're a bit faster in a lot of tests, but they're too noisy.)

    4) Ignoring the echo in the recordings (MP3 compression can cause some funky artifacts), listen to the Maxtor 10 - Ouch! That thing is killer loud.
    Reply
  • JonB - Thursday, April 21, 2005 - link

    Since my motherboard SATA controllers don't support NCQ, I have three choices. Leave it disabled (which doesn't seem so bad in some respects), get a new motherboard, or add a Promise or Adaptec PCI controller card.

    Anybody got experience with an add-in Promise RAID with NCQ support???
    Reply
  • smn198 - Thursday, April 21, 2005 - link

    #28 - "Maybe we're seeing no boost with NCQ because of poor implementation, who knows. Testing with just one platform will not reveal such issues."

    I seem to remember Anand saying the opposite
    http://www.anandtech.com/cpuchipsets/showdoc.aspx?...
    "What's truly impressive, however, is the reduction in average response time - up to a 90ms decrease in response time, thanks to NVIDIA's superior NCQ implementation. "

    However, Anand did mention that NVIDIA took the decision not to 'turn on' NCQ until the queue depth had exceeded a certain amount. (Cannot remember which article that was in.) It may be that in some of these tests, this queue depth was not exceeded.

    #30 - "How is the 7200.7 120Gb drive louder then a Raptor? My 7200.7 120Gb drive is near SILENT, no where loud as a Raptor. I think your measuring device is off forthe Acoustics test."

    This may be due to the fact that the noise the Raptor emits is at a different, more audible frequency.
    Reply

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