by July 9, 2003 0 comments



You have the best hardware in place with the best processor, best motherboard, and loads of RAM, but still your system is not giving that extra byte of performance you want while doing audio ripping and MP3 encoding, video capture and editing, DVD encoding, running CAD/CAM applications or using programs like Photoshop, Premiere, etc.

So what could be the problem? Well, all the above mentioned applications and even normal productivity applications need to do a lot of file I/O to and from the storage medium on your system, i.e. the hard disk drive. It’s therefore important to understand how to configure the hard drive to get the best possible performance. Not only that, but today you also have a choice between the new Serial ATA (SATA) hard drives or the age old Parallel ATA (PATA) ones. Moreover, you can even configure RAID on desktop motherboards today using these standard hard drives. There are motherboards that ship with
on-board RAID controllers, and you’ll even find PCI RAID cards for the ones that don’t.

Serial ATA vs Parallel
ATA

  BW 2001  Winstone
Units
CCW
2001Winstone Units
WB99/Business
Disk WinMark Thousand Bytes/Sec
WB99/High-End
Disk WinMark Thousand Bytes/Sec  
Parallel 
ATA
75.5 107.2 10600 48100
Serial
ATA
75.9 107.1 10100 46400
BW:
Business Winstone, CCW: Content Creation Winstone, WB: WinBench

Looking at so many different options, we were curious to know how much boost each one gives to a PC’s performance and which gives better throughput. We started with an aim to improve disk throughputs and along the way came across some very exciting trends in disk input/output, especially after configuring RAID on the desktop.

Our Setup
All tests were done on an Intel 875PBZ motherboard (also reviewed in this issue) with P4 3.0 GHz (800 MHz FSB), 512 MB Dual Channel DDR 400 SDRAM and NVIDIA GeForce4 graphics card with 128 MB VRAM. We used such a good configuration so that there were no other system bottlenecks other than the hard disks.

To compare the performance of serial ATA drives against the standard parallel ATA ones, we used Maxtor Diamond Max Plus 9 parallel ATA/133 and serialATA/150 disks of 200 GB each. Besides the interface, both had 8 MB cache buffer and the same internal geometry of cylinders/heads/sectors.

To understand the benefits of RAID, we configured RAID with two Seagate Barracuda ATA IV parallel ATA 40 GB disks, each having 2 MB cache, using a PCI RAID card. We also configured two Seagate Barracuda serialATA V 120 GB disks, each having 2 MB cache, using the motherboard’s on-board RAID controller.

How
hard drives store data
Data
on a hard disk starts getting filled from the outer cylinders
to the inner cylinders. As more area can be covered on the
outer tracks than the inner tracks for the same amount of
rotation, data transfer rates on the outer tracks is faster
than on inner tracks. So disk transfer rates are more at the
beginning of the disk than at the end. If you have a big hard
disk and have multiple partitions, then the beginning
partitions will give better performance than those on the
inner sides of the disk. This can be seen from the graphs
given below. These are graphs of WinBench 99’s disk transfer
rate test. Here, the transfer rate is measured from the
beginning till the end of the drive in MB/sec. That’s why
you’ll notice the hard drive capacity plotted on the X-axis,
and the transfer rates on the Y-axis. 

The thing to note in these
results is the difference of transfer rates between using RAID
and single drives. While the transfer rates in single drives
start at around 40 MB/sec and end at around 25 MB/s, they
start at around 80 MB/secs in RAID and end near 45 MB/sec. So
using RAID is just about doubling the transfer rates.

Parallel
ATA RAID

Single
Parallel ATA Hard drive

Serial
ATA RAID

Single
serial ATA hard drive

The benchmarks include the regular office productivity test suite Business Winstone 2001, high-end applications test suite Content Creation Winstone 2001, and the latest version of WinBench 99 for checking the throughput. 

The Test Results
Coming to results of the various benchmarks, in the comparison of single serial ATA and parallel ATA drive performance, we found that though the serial ATA drive had a faster interface than the parallel ATA one, there wasn’t much of a performance difference between the two. In fact, we noticed the serial ATA drive’s performance drop in some of the benchmarks. Going by this, the interface shouldn’t be the sole factor when choosing a hard drive. Other important factors like the rpm and disk cache buffer should also be considered.

RAID vs. Single drive
The days of RAID being the domain of servers are now passé. Today, you can setup RAID on the desktop using two ordinary parallel or serial ATA drives. In our results, we noticed that the performance improvement in the real world application benchmarks (BW and CCW) wasn’t very much. However, it was quite significant in WinBench 99. This is because WinBench just stresses the hard drive, and therefore gives a better representation of its true capability. So if you have an existing system with a parallel ATA disk and you want to improve disk performance then going in for another hard drive of similar specs and a hardware RAID card is a good option. Plus, IDE RAID cards are not very expensive.

Like parallel ATA RAID, you can also get serial ATA RAID to get much better performance. If you are planning to buy a new system, then going for a SATA drive and a motherboard with onboard RAID 0 controller is a wise choice. That way you can then add another SATA drive later whenever you need RAID.

SINGLE DRIVE VS RAID 0

  BW 2001 
Winstone Units
CCW
2001Winstone Units
WB99/Business
Disk WinMark Thousand Bytes/Sec
WB99/High-End
Disk WinMark Thousand Bytes/Sec  
Single
PATA Drive
70.4 102.7 8040 28400
PATA
RAID Drive
74.1 106.3 9930 36100
%
improvement
5 3 19 21
Single
SATA Drive
79.8 105.6 13100 34000
Single
RAID Drive
84.8 107.7 17800 46000
%
improvement
6 2 26 26

To Conclude
The current generation of serial ATA drives don’t provide a major performance boost over existing parallel ATA drives. So if you want better performance with a single drive, you may have to wait for the 300 MB/s serial ATA drives, or configure two of the existing ones with RAID 0. 

Till now there have been talks of increasing RAM to improve performance, but now you can also add another hard disk with RAID for the same. For those of you who have two disk drives and do not want to spend more on a RAID card, you can also configure RAID using software. We’ve explained how in the next article.

Anoop Mangla

Issues with RAID setup on XP 

Windows XP by default does not come with drivers for Serial or parallel ATA RAID controllers. So when installing XP on disks connected to these controllers, the installation does not detect them, even though the BIOS shows the disks as connected. The hardware we used (A Promise SMARAID controller and the Intel 875PBZ motherboard) came with drivers for XP. Strangely, XP was not able to recognize the hard drives even after we provided it with the appropriate drivers. We found a slightly longwinded workaround to this problem. In order to make XP recognize the RAID controllers, we first had to install Windows 2000 on the machine. During the installation, we provided it with the Windows 2000 drivers for the controllers provided by the vendors and it loaded without a hitch. We then installed XP on top of Windows 2000 and it worked fine after that. Though we faced this issue with the hardware we had, we felt that this might also occur with hardware from other vendors.

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