No Speed Benefit in ATA/133 over ATA/100?

PC World has reported in its current issue (April 2003, p. 98, bottom) that there’s no real speed gain to be realized from using an ATA/133 controller and hard drive over an ATA/100 interface.  I’ve actually been postponing my upgrading-to-a-new-Dell decision waiting for Dell to advance its motherboards (and hard drives) to ATA/133.  

In fact, I recently bought an additional hard drive (Maxtor 120GB, 8Mb buffer) for my current PC (Gateway 450) that’s an ATA/133, and I got this new drive at CostCo!  I figured it was a no-brainer that a 1/3 increase in data transfer (100MHz to 133) would translate into a real increase in overall speed in the future.  I was assuming that moving this new Maxtor ATA/133 drive to my new-someday-Dell-at-ATA/133 would pay off in speed benefits.

Is PC World correct?  Are they right that there’s no real value in waiting for Dell to upgrade its motherboards to ATA/133?  Thus, ATA/133 offers no improvement over ATA/100?

Then, can I conclude that my new Maxtor 120GB, ATA/133 would really be no slower in a new Dell ATA/100 than it would be if Dell’s new PC’s had an on-board controller at ATA/133?

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WakeupSpecialist 1Commented:
I disagree with PC World.  We've done some benchmarks and the 133 usually performs better in most circumstances.  Maybe not as much as we'd like...but yes it does.  Here are some examples:

Again, grant it the numbers aren't greatly increased, but it is true 133 is faster in most cases.  So the other question now it worth the difference in price to go from 100 to 133?  Depends on you.
Yes and no.  These days the bus speed of a drive is really a small part in the chain of performance.  There are plenty of synthetic benchmarks that will show a marked improvement in speed of a ATA133 bus over a ATA100 bus, but those are almost always pure cache hit data transfers, meaning only accessing infor that has been stored in the drives onboard memory in prediction of what info the system may need.

Where your real speed increases are going to come from are spindal speed and areal density.  Spindle speed is the simplest way to increase drive speed since more physical area passes under the head at a given time, therefore logically increasing data transfer as well as reducing latency while you, the system, and the drive wait for the requested data to finally make it back to the head while the platter is spinning.  Areal density can also make big impacts on transfer speed since, not unlike a faster spindle speed, more data is simply passing under the head at a given time, which also increases drive capacity.  Number of platters can also make a difference in drive speed when engineered to do so since the same ammount of data that passed under the two heads of a platter is now being multiplied by the number of platters the drive contains (as a side note, IBM recently (before selling their HD market to Hitachi) started adding platters to drives for internal mirroring to achieve a semi-Raid-like redundancy.)

So, as you can see, there are a lot more factors in HD technology that govern transfer speed than simply bus speed.

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Sometimes the first issue of a newer drive will have lower RPMs. So an older drive with highers RPMs can be able to transfer as well as the newer. Vice versa, the newer drive can seem to be as slow as older drive when its seek time and/or RPMs are lower.
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In addition to all the above, Cache buffer size may make a difference, depending on file size and type of testing.

If you went from a 7200 RPM 2 MB cache to a 7200 RPM 8 MB cache, you may see an increase on the benchmarks and maybe even in real like, independent of the ATA speed.

I hope this helps !
File system cluster size also plays a significant role in hard disk performance.  A smaller cluster size means less wasted space being passed under the heads which transfers to shorter read times.
WSCAuthor Commented:
Hi WakeUp,

Thanks for the response.  My dilemma is that I'd like for Dell to upgrade its motherboards to ATA/133 and I've been waiting for more than a year for this to occur.  It just doesn't seem to be happening. I thought it was a no-brainer as ATA/133 drives and motherboards have been out for at least 18 months. I'm not sure what's holding up Dell.  I'd be willing to pay more, but $$$$ are not the problem.

MatGuy seems to disagree, saying these benchmarks don't really translate into a real increase in over computer processing speed.  All of the drives (my new one as well as the ones Dell offers) are 7,200 RPM w/ 8MB cache.

JWitt98: I think the same article in PC World recommended a cluster size of 32 - 64.

So, is Dell going to upgrade its motherboards to ATA/133 the day after I purchase?  ;) If so, will they be de facto faster?
I just don't think that ATA 133 support should be a deciding factor in a system purchase.  If you really need the 133 support you can always go pick up an ATA 133 PCI card.
WSCAuthor Commented:
Matguy: You may be right.  The best Dell box comes with only 4 PCI slots and after adding a firewire, soundcard, and some type of adaptor card for pulling in analog video, that only leaves me with 1 open slot. I'd hate to have to waste it on an ATA/133.  

Are you sure an ATA/133 card will run at 133 if the motherboard itself is only ATA/100?

After reading the "Tweaking" article, they concluded that ATA/133 didn't offer any advantage over ATA/100 at all. Strange.
"Are you sure an ATA/133 card will run at 133 if the motherboard itself is only ATA/100?"

Yes.  The ata100 of the board comes off the chipset and logically connects as a PCI device (generally.)  Adding a ATA133 PCI card connects to the chipset as a PCI device as well and the system will access it like any other card, and in some ways treat it like a SCSI card and utilize as much bandwidth as the PCI bus can provide reguardless of the connection specification.

(side note: it just occured to me that you may have not dealt with PCI IDE cards, what they will do is either replace or add to the IDE/ATA ports on the board, not convert those ports to a higher specification.  Your onboard ports will remain ATA100 no matter what you do.)
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