iMac AL 24" Hard Drive Swap - Pics/Procedure inside

[IBitePrettyHard]

Wow, just like open-heart surgery. I hope my 24" never has to be rushed to the emergency room

[raysmd]

I am very surprised at the benchmarks. If you read the reviews on storagereview.com about the particular drives it seems that the seagate is not a favorite.


[EDIT]
Well, I can't compare apples to oranges. The drives that they reviewed were the 16MB cache versions. The WD that ships with the iMacs is 8MB

[joebells]

Originally Posted by raysmd

I am very surprised at the benchmarks. If you read the reviews on storagereview.com about the particular drives it seems that the seagate is not a favorite.


[EDIT]
Well, I can't compare apples to oranges. The drives that they reviewed were the 16MB cache versions. The WD that ships with the iMacs is 8MB

If you read the results they say that the original drive was in an external enclosure when tested that will greatly reduce the speed. I thought the speeds posted for the original drive were way too low and then looked and saw it says external.

[negatv1]

Yeah, benchmarking the WD drive is not fair comparison using an external enclosure. Even FW800 is much slower than native SATA.

Here are the xbench results of the same stock WD 320gb drive (albeit in a 20inch iMac):


While I do have 2x the RAM, it shouldn't affect the disk performance I wouldn't think.

So, upgrade for capacity... not speed.

[Tom Sawyer]

Originally Posted by negatv1

Yeah, benchmarking the WD drive is not fair comparison using an external enclosure. Even FW800 is much slower than native SATA.

Here are the xbench results of the same stock WD 320gb drive (albeit in a 20inch iMac):


While I do have 2x the RAM, it shouldn't affect the disk performance I wouldn't think.

So, upgrade for capacity... not speed.

The external USB 2 enclosure shouldn't slow the drive down... it's 480mb of bandwidth (1 megabit = 0.125 MB) so that's 60MB of bandwidth, plenty enough for a single SATA 7200 rpm drive. That said, this enclosure may not be the greatest... though it is a WD enclosure!!

EDIT: Just noticed that you posted the results from a 320gb.. .Thanks! I can't imagine that RAM would affect the #'s like that either.. .I'm really surprised. Perhaps it is the 16mb cache that is helping matters out here and making things faster in the OS? Would have thought the benchmarks would reflect that. I just found that WD is actually making drives now with Perpendicular tech as well. Here are some bench results comparing the WD and the Seagate directly. Both 320's, both 16mb cache drives, etc. Seems like a mixed bag on who comes out on top.

WD - Seagate Comparison

I'm sure there are overheads and "best case" we get 60MB of bandwidth on USB 2.0. Marketing and actual can often differ.

[joebells]

just because usb 2.0 has that bandwidth doesn't mean a hard drive can get that bandwidth. A drive in an external enclosure will not come close to an internal drive. It takes different paths through the computer and such. The Hard Drive controller on the logic board for the hard drives is setup to process the hd requests and it has better connections to the rest of the system. So you have the overhead of the drive going through the usb controller on the logic board. Plus many external enclosures aren't great either and so you have slow down there also. Then the OS also is optimized first for HD's connected by sata,ide, scsi. USB is just a medium for adding things.

You can never compare the speed of a drive that is internal to one that is in an external enclosure. You're access times will suffer the most as well as transfer speed.

Now if you had the drive hooked up with an eSata connector I believe that would come pretty close but alas the imac doesn't have a spot to connect it.

And no the amount of memory won't impact the scores the test should be straight cpu to hd as its not really writing anything useful to the drive.

[Tom Sawyer]

Originally Posted by joebells

just because usb 2.0 has that bandwidth doesn't mean a hard drive can get that bandwidth. A drive in an external enclosure will not come close to an internal drive. It takes different paths through the computer and such. The Hard Drive controller on the logic board for the hard drives is setup to process the hd requests and it has better connections to the rest of the system. So you have the overhead of the drive going through the usb controller on the logic board. Plus many external enclosures aren't great either and so you have slow down there also. Then the OS also is optimized first for HD's connected by sata,ide, scsi. USB is just a medium for adding things.

You can never compare the speed of a drive that is internal to one that is in an external enclosure. You're access times will suffer the most as well as transfer speed.

Now if you had the drive hooked up with an eSata connector I believe that would come pretty close but alas the imac doesn't have a spot to connect it.

And no the amount of memory won't impact the scores the test should be straight cpu to hd as its not really writing anything useful to the drive.

Very true... it sounds good when "they" tell us USB 2 is 480 or FW800 is 800, but there is more to it.

Yeah, wouldn't think ram (past a certain point) would affect HD speeds at all.

[Tom Sawyer]

My project expanded a bit last night... so now I have the Panel Make/Model:

My machine has an LG/Philips Model LM240WU2 (SL/B1)

Here is a shot of the label:

[JimmyDreams]

Originally Posted by Tom Sawyer

DOH! I was so focused on the task at hand that I completely forgot to look at the back of the LCD for the make/model.

Take your iMac apart again and look!! Answer the guys question!!! Jeez....


SLACKER!!



(that's humor folks! Tom has enormous cajones!)

JimmyD

[Tom Sawyer]

Originally Posted by JimmyDreams

Take your iMac apart again and look!! Answer the guys question!!! Jeez....


SLACKER!!



(that's humor folks! Tom has enormous cajones!)

JimmyD

Funny you should mention that JimmyD... See post above... <Evil Grin>

[JimmyDreams]

Originally Posted by Tom Sawyer

Funny you should mention that JimmyD... See post above... <Evil Grin>

Enormous cajones AND fast! What a combo!!!

JimmyD


(almost afraid to even clean the front of my iMac...much less take 'er apart!!!)

[negatv1]

I knew there was no way that the WD320gb was *that* slow. I'm sure that a Raptor could be made to look lousy in a USB external enclosure. Somewhere within the USB->SATA bridge chip of just limitations of USB 2.0, you're just not going to get any kind of performance out of USB 2.0 and disks.

FW400 is better, FW800 even better - but still not at par with native SATA (or PATA).

[imacdaddy]

Originally Posted by Tom Sawyer

My project expanded a bit last night... so now I have the Panel Make/Model:

My machine has an LG/Philips Model LM240WU2 (SL/B1)

Here is a shot of the label:

Thanks for this!

So what did you do to your iMac?

[Tom Sawyer]

Originally Posted by imacdaddy

Thanks for this!

So what did you do to your iMac?

Well, as luck would have it my new drive seems to have an issue. I mentioned noticing noise/vibration. Well, it has progressively gotten worse until there was a low frequency hum coming from the iMac that I could hear across the room. I'm sure the back was acting like a baffle and amplifying it, but it got worse. If I listened to the mac at about center, it sounded like the hum from a transformer. So, I ended up pulling a 750 from an external enclosure I had bought back with Best Buy was selling them for $199 (this is also a 7200.10 drive). I really didn't need THAT much space in the iMac with having a NAS but was planning on using it for a video drive, etc. Anyway, thus the 'extension' to my project. The good news is that the 500 is under warranty so have an RMA on that and the 750 is silent with 0 vibration as it should be. Oh well, part of the risk when you DIY on these things.... I put the 320gb WD in the seagate enclosure and will sell that to a friend for $60 bucks. Will probably just sell the 500gb when I get the replacement since I have more than enough space in the iMac now..

[daneoni]

Originally Posted by negatv1

I knew there was no way that the WD320gb was *that* slow. I'm sure that a Raptor could be made to look lousy in a USB external enclosure. Somewhere within the USB->SATA bridge chip of just limitations of USB 2.0, you're just not going to get any kind of performance out of USB 2.0 and disks.

FW400 is better, FW800 even better - but still not at par with native SATA (or PATA).

Is the SATA II/PATA interface the same (in terms of bandwith/speed/capability) in both Notebooks and Desktops?

Also why are desktop drives much faster than their notebook counterparts?

[Tom Sawyer]

Originally Posted by daneoni

Is the SATA II/PATA interface the same (in terms of bandwith/speed/capability) in both Notebooks and Desktops?

Also why are desktop drives much faster than their notebook counterparts?

PATA topped out at about 133 mb/sec (ATA133)... SATA II is 300 mb/sec according to the spec. At the end of the day, there are no single drives out there that even begin to tap out ATA133 much less SATA II speed (given they are connected to the interface they are designed for)... the real number that matters is platter to buffer x-fer rate and even the fastest 15k scsi drives push up to about 150 mb/sec. The interface speed (how fast the drive electronics can push to any given drive interface, IDE, SCSI, SATA, etc) is always beyond what the physical drive can push. Where the interface speed is important is when you start building RAID arrays with multiple drives capable of large transfer rates... you can saturate any given bus.

Historically, laptop drives were slower due to their much slower spindle speed. They started out like 3200.. then 4200.. Generally 5400 is the slowest (give/take) these days and of course 7200 rpm laptop drives are becoming popular. I know Seagate makes a 7200.2 (had one in my recently departed Inspiron E1705) and it was the first laptop drive to use Perpendicular technology. For a laptop drive, it was amazingly quick. Platter size may contribute to a 2.5" drives lag in performance as well.

I've always been big on hard drive performance, have had SCSI U2W setups in a number of PC's before the days of faster IDE/SATA drives.. have had raid 0 raptors in gaming rigs, etc... Drive speed is still the bottleneck to system performance.

[daneoni]

<snip>

Ah i see, makes sense now.

FWIW the WD seems to hold its own very well, its decently fast (most apps launch in one or two bounces)and has decent storage. Overall, its seems to have a good performance/storage ratio. Then again, am probably just saying this cos i haven't been exposed to anything faster as of yet

[Tom Sawyer]

Originally Posted by joebells

holy crap it doesn't seem right how slow the old drive was.

EDIT: I see the old drive was hooked up externally. Thats not really a fair comparison

Very true... there was another post with an internal result... it did better than I thought it would have. Still, the seat of the pants benchmark says the Seagate is quicker but it may be the cache helping out. Still very pleased with the upgrade, and it sure was cheaper than letting apple do it!!!

[Tom Sawyer]

Originally Posted by BennyK

I am amazed that you were the first with the balls to take it apart. You are da man!

Thanks... really it was far less intense that I thought it might be. The second time took 20 minutes tops!

[psonice]

It's good to see that the HDD is not too hard to replace. How about the CPU though, is it swappable when fast quad core chips are available in a year or two? I'm guessing nobody is prepared to take the warranty sticker off the heatsink yet to find out

[Tom Sawyer]

Originally Posted by psonice

It's good to see that the HDD is not too hard to replace. How about the CPU though, is it swappable when fast quad core chips are available in a year or two? I'm guessing nobody is prepared to take the warranty sticker off the heatsink yet to find out

I tried to see it while I was in the machine but too much in the way. I would guess it would be a matter of just further disassemble and popping out the old chip and putting in the new one. I'm sure they socketed the chip but the warranty sticker would be toast. I'm definitely planning on swapping the CPU after the warranty is up as well.

[indiekiduk]

I wouldn't replace a Western with a Seagate, no way! Seagate are now the noisest drives on the market since they were pressured into removing Acoustic management from all drives since 2003 (ish) because of the patent breach.

[Tom Sawyer]

Originally Posted by indiekiduk

I wouldn't replace a Western with a Seagate, no way! Seagate are now the noisest drives on the market since they were pressured into removing Acoustic management from all drives since 2003 (ish) because of the patent breach.

While it does make more noise than the stock WD, it is by no means loud. As quiet as the iMac is, I think a loud drive would be very noticeable (thus why the first defective one was removed). They are still relatively quiet drives and most importantly the sound they do make is not annoying.

All modern drives are so quiet in comparison to those we used a few years ago before fluid dynamic bearings. I remember enduring tortuous whine from fast SCSI drives back in the day...

[Tom Sawyer]

Originally Posted by negatv1

Yeah, benchmarking the WD drive is not fair comparison using an external enclosure. Even FW800 is much slower than native SATA.

Here are the xbench results of the same stock WD 320gb drive (albeit in a 20inch iMac):


While I do have 2x the RAM, it shouldn't affect the disk performance I wouldn't think.

So, upgrade for capacity... not speed.

How large was the partition you tested on? The results seem to vary based on partition size from the testing I've done on these drives.....

[joebells]

The size of the partition shouldn't make a ton of difference what can make a difference is wether the partition is on the inner part or outter part of the platter(s).