Why is new iMac G5 so slow with LIVE????

noisetonepause · Post by **noisetonepause** » Sat Oct 09, 2004 4:48 pm

rand wrote:Anyone with 1/2 a clue knows that OSX (& I believe XP) needs at least 1gig ram to run well. It also needs a few gigs free on the HD for it's memory swaps.
rRand

Haha.

Here's what 'top' says, running from my tcsh terminal under OSX.3.latest:

PhysMem: 48.7M wired, 125M active, 172M inactive, 347M used, 36.9M free
VM: 2.63G + 86.2M 31067(0) pageins, 0(0) pageouts

This was running Safari, Mail, and Finder (and the terminal, obviously).

So no, you don't need a gig of memory to run OSX well, at least not on a G3

-Paws

tribalogical · Post by **tribalogical** » Sun Oct 10, 2004 2:52 am

yeah, but, hrmmm...

Sure... you CAN run OSX + additional apps with only 256Mb of ram....... no problemo...

The thing is, you WILL get the "virtual swap" action kicking in pretty quickly, and that will slow the whole works down (as that requires both CPU attention and delays during read/writes of the 'virtual ram' swap files from/to the hard drive)... So, yeah, you can run those with limited RAM, but you simply can't run the OS + intensive apps *at peak performance* without adding more RAM...

When you bring total RAM up to 1 ~ 1.5 Gb , you will get noticeable improvements in performance across the board, for a few reasons... less swapping (lighter on CPU), more app modules in RAM (faster), no waiting for regular file swaps.....

Beyond 1.5Gb, you won't really see additional performance specifically from adding more RAM, unless you work with vast files (video editing anyone?) which could require virtual swapping again....

And, Adam Jay is right about the "performance setting"...... with the "Automatic" setting, even when using a demanding app, the CPU will throttle itself down during any "in-between" cycles, to conserve power and reduce heat..... the act of throttling itself requires a few cycles, so adding a bunch of "up/down" actions, will end up 'stealing' performance...... it's not noticeable with most everyday apps, but can be quite apparent with our favorite music-moshing apps...

Switching the performance setting to "high" will turn off throttling.
(A caveat however: that is only true unless and until the CPU starts to overheat... then it will start auto-throttling again, regardless of setting, until the heat comes back down. It doesn't take long, generally, but can be a spoiler when you're running a Set at 93% and the throttling suddenly kicks in...!)

Anyway, that's mostly how it works, as far as I understand it.... (hey, was that a disclaimer?

)

peace,
tribalogical

forge · Post by **forge** » Sun Oct 10, 2004 9:45 am

By and large with my PC Laptop I am pretty much in a habit of changing the power settings all the time according to what I'm doing.

These power save technologies were put there for a reason because, pre-centrino at least, the desktop chips in laptops get damn hot and are more likely to overheat than in a desktop - so I prefer to let it wind down if I can get away with it - and I would hazard a guess that the reason it's taken Apple so long to sort out the G5 PB and iMac is down to heat, so being all in one thin enclosure I'd say it would be more of a consideration for the iMac than the desktop

if I'm writing for example the odd click while it winds itself up doesn't matter to me - then I just turn it to 'always' If working on an intensive project or when I don't want the PC to decide for me.

So if the CPU meter is running to 50% but there are no actual problems with the audio or GUI then I say Fugget, but get to know your powersave, it is your friend!

noisetonepause · Post by **noisetonepause** » Sun Oct 10, 2004 10:38 am

tribalogical wrote:yeah, but, hrmmm...

Sure... you CAN run OSX + additional apps with only 256Mb of ram....... no problemo...

The thing is, you WILL get the "virtual swap" action kicking in pretty quickly, and that will slow the whole works down (as that requires both CPU attention and delays during read/writes of the 'virtual ram' swap files from/to the hard drive)... So, yeah, you can run those with limited RAM, but you simply can't run the OS + intensive apps *at peak performance* without adding more RAM...

When you bring total RAM up to 1 ~ 1.5 Gb , you will get noticeable improvements in performance across the board, for a few reasons... less swapping (lighter on CPU), more app modules in RAM (faster), no waiting for regular file swaps.....

Beyond 1.5Gb, you won't really see additional performance specifically from adding more RAM, unless you work with vast files (video editing anyone?) which could require virtual swapping again....

I know about swap files and why they're evil

What I'm saying is this: with OSX and Live as the only running apps and most clips coming off hard disc as opposed to RAM, you don't need a gigabyte of RAM, just like you don't need it for regular desktop use.

-Paws

raapie · Post by **raapie** » Sun Oct 10, 2004 1:14 pm

I don't understand a few things. If I am correct Live doesn't support dual processors. So a dual G5 would perform the same as a single G5. These new iMac all are using a single G5-cpu. I have seen Live performce tests based on the G5 which are much better than the performance of the G5 iMac.

How come?

noisetonepause · Post by **noisetonepause** » Sun Oct 10, 2004 1:24 pm

Busses, probably. The iMac cuts a few corners there to keep the price down. The iMac has a 600 MHz busses, I think, but the Powermacs have them at half the frequency of the CPU, and one for each processor.

Also, the OS will take advantage of the dual processors, I'm quite sure.

-Paws

rand · Post by **rand** » Sun Oct 10, 2004 3:58 pm

(dup)

PookyNMR · Post by **PookyNMR** » Sun Oct 10, 2004 9:45 pm

OS X is a hog. It works great and looks pretty, but it's a hog.

You NEED 512 MB RAM for basic OS X operation. You need at least 1 GB (or more) if you're going to be running a DAW w/ FX, VSTi, etc, etc. These things take RAM.

Tribal's post was great.

Nathan

AdamJay · Post by **AdamJay** » Sun Oct 10, 2004 10:12 pm

so why is apple selling a $2000 desktop with only 256MB then ?

guatamaham · Post by **guatamaham** » Sun Oct 10, 2004 10:16 pm

rand wrote:It is fact that 1 gig or more ram will make OSX fly MUCH faster & smoothly.

this is partially true... see OS X, like linux and unix, uses an aggressive caching strategy - nothing is removed from RAM until something has to be in order to put something else in. which means that if you have more RAM, more applications can stay in RAM (even once they've been closed) and thus they will start faster. now of course your machine will run better with more RAM (so will windows). duh!

but that doesn't mean its useless with only 256MB of RAM. if you only have a couple of "normal" applications (safari, email, itunes) open at once, you won't see much difference. you will see a difference in startup times for apps, though. and you should see a difference in Live, if you choose the option of keeping clips in RAM. in other words, Live with 256MB of RAM (and keeping very few clips in it) versus live with 1+GB of RAM (and keeping a lot of clips in it) should be pretty different.

and on the subject of Apple having a ~$2000 machine w/256MB of RAM.... I agree that they should have more. BUT you should remember that the iMac G5 is only ~$600 more than just buying the screen would be (20" screen = $1200; 20" iMac = $1800). and that's quite something, given what the processor is. and Apple is kind of doing you a favor this way anyway - their RAM can be bought elsewhere for cheaper (as is true for PC manufacturers as well).

and I personally don't have a problem with Apple's performance. remember that the G5 cluster ranked in the top 10 amongst all supercomputers in the world. and if I remember correctly, it was the only cluster in the top 10 (so it beat numerous Intel and AMD clusters). the only problem is that sometimes cross-platform apps (like Live) don't run as well on Apple as on windows. and this is probably due more to coding decisions made by the developers in the design of a cross-platform app than anything else.

PookyNMR · Post by **PookyNMR** » Sun Oct 10, 2004 10:38 pm

AdamJay wrote:so why is apple selling a $2000 desktop with only 256MB then ?

...to keep pricing lower and appear more competitive.

Nathan

noisetonepause · Post by **noisetonepause** » Sun Oct 10, 2004 11:19 pm

PookyNMR wrote:OS X is a hog. It works great and looks pretty, but it's a hog.

You NEED 512 MB RAM for basic OS X operation. You need at least 1 GB (or more) if you're going to be running a DAW w/ FX, VSTi, etc, etc. These things take RAM.

Tribal's post was great.

Nathan

But mate, how can you NEED 512 megabytes of RAM when the system isn't using it?!

Running iTunes, Safari, and Mail:

PhysMem: 50.3M wired, 151M active, 149M inactive, 351M used, 32.7M free

Explain the idiot (me) now. My system isn't using all the memory - why do I need more?

-Paws

PookyNMR · Post by **PookyNMR** » Mon Oct 11, 2004 4:03 am

OS X has dynamic memory allocation. It will always leave itself enough headroom. On systems where there is less physical RAM it will use the hard disk to store the data. So physical RAM usage is relative to what is available on the system.

Run this test using the system monitor and notice the difference.

DAW host re-wired to LIVE. Have 24 tracks loaded on on the DAW host, a dozen tracks on LIVE. Put lots of insert and send FX on both. If you have a soft-samper, run that too. Now if you have a system that has 1 or 2 GB of RAM, look in the system monitor and see how much resources your system (OS) is taking up. The numbers will be much higher as more parts of the OS will be in use for the more intensive applications.

Nathan

noisetonepause · Post by **noisetonepause** » Mon Oct 11, 2004 7:50 am

I'd run it (and I'd use top in the terminal - real man use the terminal), but Live is my only music programme right now. I suppose I'll have to take your word for it... I still maintain that 256 MB of RAM is enough for web browsing and word processing and organising your holiday snaps, which is pretty much all 90% of the new iMacs will be used for...

-Paws