To segment or not

Hi Dan;

Assuming that when you say segment you mean partition then I would suggest not partitioning the system disk. It only causes problems and reduces performance.

Allan

Hi Dan;

You are welcome.

I just wanted to be sure we were not talking at cross purposes so that is why I asked for clarification on your "segment" term.

Allan

Hi Dan;

It is me again.

Exactly which version of Photoshop are you using?

If you use PS CS2 with Tiger, PS is now using memory management from Tiger and the performance is much better. It doesn't use scratch nearly as much as it used to. I have found that this combination gave me enough of an improvement in performance so that I was able to put off my upgrade to the G5 until the spring.

Allan

Dan,

There is no performance or reduction of defragmentation benefit with partitioning anymore. Tiger defragments most files on the fly and a Photoshop "scratch" actually requires a very fast seperate drive or RAID O because the purpose of it is to simulate RAM as PS had a RAM limit.

Tiger over rides CS2's RAM limit (CS2 only unfortuantly) and alllows you to use all you need that you have in your Mac, so load up on the RAM instead. Forget scratch, turn it off. RAM is incrediably faster.

Now if your interested in Mac OS X performance I can give you some tips:

1: Mac OS X is heavily cache and swap dependant, so a slim fast boot drive will give snappy response. (Boot/apps/iTunes music/bare bones "home" on a 74 GB 10,000 RPM Western Digital Raptor)

2: Keeping one's bulky user created files (documanets, pictures, movies etc) in NEW folders on the original drive will allow you to use two drives at once. The small size of the Raptor will keep you from overfilling it, thus the OS will remain snappy. The larger, the slower and the more filled a boot drive is, the slower Mac OS X becomes.

3: Clone the boot drive to a external drive and make backups from the file drive. This way you can boot from the external in case of problems.

4: Extreme performance can be achieved using two Raptors in a RAID O as a boot/all drive, but limited to 148GB and one must clone regularly as the failure rate can be slightly higher than normal drives as the data is stripped across both drives. (mine has been fine for over a year)

5: Using less than 50% of a drive is optimal performance for that drive, one shouldn't use more than about 80% of a boot drive because Tiger needs a bit more room for auto defragmentation/swap/cache.

6: Disk Utility Erase w/Zero option all drives the first time to rebuild the bad sector map in case the manufactorer "forgot".

some detailed links

http://discussions.info.apple.com/webx?128@@.68ba240f

http://discussions.info.apple.com/webx?128@@.68b96845

ds store, "Raptor question" #1, 07:00pm Oct 4, 2005 CDT

Hi, Dan!

DS provided some excellent advice.

I believe that his third performance tip was to use an external drive as a bootable clone of your start-up drive for backup purposes, rather than for regular use as your start-up drive. It will not only protect the data on your main/internal drive, but will also allow you to boot from it should you have a problem with the main drive. Thus, you could be back up and running in minutes, rather than after hours or days of troubleshooting. (You would also have the option of re-cloning the clone back to the main drive, if you ran into a problem that was messy and not easily fixable.) The reason for using an external for this is that the drive is normally disconnected and not running, and not very likely to be subject to ills such as power surges, drive failure, etc., providing another level of safety for your data.

The WD Raptor was recommended because it is extremely fast, arguably the fastest drive currently available in the general marketplace.

Gary

You lost me a little when you got to item No. 4. In trying to understand your suggestion, I take it that you're recommending that I install an external drive, put my OS on that drive, assign it as the start-up drive, and keep everything else on the factory-installed hard drive. Was there a particular reason you chose the Western Digital Raptor model, or will any reliable manufacturer's drive do the job (for example, a LaCie drive)?

Sorry #4 is a different suggestion from #1 and #2 requiring two 74 GB 10,000 RPM internal drives in what's called a "stripe" (or RAID O) in Disk Utility, it's a substantial drive performance increase that may be unsuitable for your needs. (185 MB p/s uncached writes)

Suggestion #1 and #2 is in regards to having one 74 GB 10,000 RPM drive as a boot/app/itunes/bare bones "home" drive and keep your movies, documents, pictures and other bulky stuff on another internal drive in new folders. (80 MB p/s)

What's nice about having the first 74 GB 10,000 RPM Raptor as a boot is later if you need extreme performance you can just get another Raptor and make a "stripe" of the two.

Disk Utility will stripe what drives you want, but matching drives, performance, and interfaces should be followed for best results.

The reason the Raptor is picked is because:

1: It's the fastest drive available that's internal SATA and fit's in your machine.
(if Lacie has a internal 10,000 RPM 74 GB SATA drive then of course this will do as well, it's just Western Digital was the first out with these drives)

2: The 74 GB size keeps it small and is excellent as a boot only drive. When you use a large 250 GB 7,200 RPM drive and fill it up, over time Mac OS X performance will suffer due to the reasons given in #1.

RAID O or striping two large drives like 250 GB 7,200 RPMs will give slightly better performance (80 MB p/s writes), but it will degrade quickly as the combined 500GB is filled up and takes considerable time (several hours) to clone the whole mess to a external drive for backup.

Oh another performance thing you can do is do a fresh install of Tiger and upgrade (via Apple downloads page) to 10.4.2 in addition to the Raptor boot install. Don't use software update to go to 10.4.3, there is plenty of issues with this update circulating the Mac internet.

(if you decide to do Tiger, update all your hard drive driver software by visiting the drive makers site before connecting thrid party drives to a Tiger boot drive)

Keep your original Panther OS on a disconnected drive and work your way into Tiger as you might forget somethings and have to boot into Panther.

On your G5 you should see a slight CPU performance increase and a substantial user interface performance increase (Safari too 🙂 ) with Tiger over 10.3.9 Panther. (as tested with x-Bench)

Your new machine will have Tiger already pre-installed. Take a firewire 400/800 cable and connect the two and T boot the Panther box.

Follow my instructions to carry info from the older box here

http://discussions.info.apple.com/webx?128@@.68ba240f

Migration Assistant can help, but doesn't offer fine control and a lot of apps are either copy protected or you need a fresh Tiger version.

Thanks for this help.

Your welcome, sorry if I'm talking over your head a little and sending a ton of info your way in a sort of a confusing manner (it's the hurricane effects, I had two feet of water in my house and it's been downright wierd lately 🙂 )

I thought I noticed someone saying that if the OS was located on the same disk as all the work files, the system could slow down. If that were true, it would present some difficulty for those whose computers only have the installed hard drive available.

Yes it will and this is the reason.

Drives save data in the first available free space. With Mac OS X most files are written to the first available free space that can hold the entire file.

What happens over time is de-optimization, OS files get strewn all over the drive and takes longer to gather over a large drive.

Also as a big drive gets filled up, it takes longer to move the drive heads to the free space at the center of the drive platters to write swaps or caches and then all the way back to OS data at the outer rim of the drive.

Having a small, fast boot drive with ones bulky (documents, pictures, movies etc) files in new folders on a second drive solves this problem marvelously and has additional performance benefits as two drives can be accessed at once instead of "wait for A until do B" with everything on one drive.

I currently have my hard drive partitioned into Macintosh HD, which hold the OS and Applications, and a Workdisk, which contains all my working files.

This may help reduce de-optimization, but really offers no performance benefit because your using the same drive heads and one pipeline interface for both partitions.