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Hard Drive Performance - ATA100 vs ATA133
Tweaker writes "A short visual guide to the performance advantages of ATA133 over ATA100. Synthetic and real-world benchmarks are also included."
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Well, the tests show near-identical performance between ATA100 and ATA133, with ATA133 occasionally performing worse than ATA100. So, it could be just the test system, but, I'm going go to SCSI anyway.
Besides, hardware RAID is fun :-)
How many ATA drives out there actually get anywhere near 133MB/s sustained transfer rates from the media? Any even able to sustain half of that? Not that I've seen.
For ATA, it's hype.
Someone might argue that it is good for RAID, which would be true for SCSI. But RAID 0 for example with two drives on the same ATA bus gives terrible performance due to the time taken to switch between ATA master and slave drives. So it really comes down to what an ATA drive can sustain.
Sure it's nice to have the fast bus in place for the future, but by then, you've probably already upgraded to something much faster still.
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No, the bottleneck is the drives.
The fastest IDE on the market is still only spinning at 7200 rpm. Maximum transfer rate is going to vary depending on the media density at the outermost track on the drive, but in general it's still not going to approach 133 MB/s. Most IDE drives have sustained data transfer rates in the 50 MB/s range (the Maxtor D740X, which is one of the most popular IDE drives on the market currently, has a sustained transfer rate of only 44.4 MB/s at the outer diameter and 24.2 at the inner, as per Maxtor's own tech sheet).
If you read the literature from Maxtor, who designed this standard, even they will admit that the maximum transfer rate will only occur on a read from cache - and the biggest cache on an IDE drive is a whopping 8 MB. So congrats on sustaining that maximum transfer rate for all of 60 ms. After that you're back to reading from disk.
The only real advantage of ATA133 is to support drives >120GB. Of course, the funny thing is that the only 160GB drive available right now is a mere 5400 RPM (with a lovely 35.9 MB/s at outer diameter).
ATA133 is widely regarded as a marketing gimick. Apparantly it's working though, since some people actually think it matters.
Uhm ... Ultra ATA 100 (ATAPI-6) already supports 48 bit addressing, thus allowing for 144 PB (that's petabytes) disks. Furthermore, it is inadvisable to connect more than one hard drive to one ATA channel, because of the crappy interface design (only one disk can transfer at a time, DMA problems). So this is nice marketing blurb, but in reality it's pointless. HDDs won't get past the 100 MB/s until at least 3 years from now, and by then Serial ATA will already be ubiquitous. Conclusion: if ATA133 comes with your mainboard, fine, but don't pay extra for it if you've already got ATA100.
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Feh. An extra 33% bandwidth. Woopee. Considering all the other factors affecting the performance of a system I really don't care unless performace is 2x of what I got, as the net effect is so diluted by the other componets of a system.
Breaking the 120 GB barrier is significant at this point the way HDD capacities have been increasing though.
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Servers use SCSI because it's more expandable, and better RAID solutions are available. It's also true that the highest end drives are SCSI, but this is more of a case where they can demand a higher price point for SCSI drives, so SCSI is the only type of drive where it's profitable to market those high end drives. The same higher density, faster spindle drive technology will eventually reach the IDE market, and will perform in a comparable fasion there. SCSI also has the advantage of being able to reorder requests so that it can access the data sequentially. There are some applications where this can be taken advantage of if the drives and HBA support it, but in general, the effect is minimal.
OK, let's say they took a 15K super-reliable server drive and put a ATA controller on it. Now why exactly is it cheaper? Sounds like the same price to me.
The basic problem is that there's different priorites for 'server' and 'desktop' drives (which the industry has mapped onto the SCSI and IDE interfaces respectively.)
Server Priorities:
1) Reliable, Long Warrantee
2) Fast
3) Expandable by adding drives to arrays
...
99) Cheap
Desktp Priorities:
1) Cheap
2) Big
3) No expansion outside of the case
4) Fast
...
99) Reliable
So we get two entirely different classes of drives. You'd like a 15K IDE drive, and I'd like a 160GB 5400 RPM SCSI drive (would fit my cabling setup better), but life ain't fair when you are outside a target market.
Oh, for the millionth time it's NOT! IDE is a very dumb interface. Only one device per channel can work at a given time. While you are reading/writing one drive, the other one does absolutely nothing. It is not possible to get sustained transfer of anywhere near 100MB/s out of IDE. This is precisely why people report no improvement in speed when going from 2x striped IDE RAID (on 2 separate channels) to 4x. If you want the 4 drives to work at the same time, you have to use SCSI.
To sum up, anything above ATA66 is a marketing gimmick (I have yet to see an IDE drive that can have sustained transfer of over 50MB/s). ATA133 is not entirely so -- it allows you to use HDs of > 120GB, but that's it.
___
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Yes, that is the real advantage, and probably the reason that ATA133 will eventually become the standard for all drives/controllers.
ATA133 will definatly NOT become the standard- parallel ATA is pretty much at the end of its road. The future standards will be with serial ATA. Where parallel ATA is reaching its limits at 133, serial ATA is planned to have speeds of 600 MB/sec within the next few years. Plus it is software compatible with the older conrollers (no new drivers), uses less power, and gets rid of those annoying ribbon cables that restrict airflow. All of the major chipset designers are moving on to serial ATA.
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