PDA

View Full Version : Would it be worth my while to go from a DP1GHz G4 PowerMac to a 1.8GHz G5 iMac?




edesignuk
Sep 22, 2004, 02:51 AM
It’s been nearly 3 years since I bought my dual 1GHz G4 PowerMac (Quicksilver – 1GB RAM, 80GB+20GB, SuperDrive, GF4MX 64MB), and it has served me well, and honestly still does do everything I need with adequate speed. But, it’s getting close to that time when I want a new Mac again! Now, I was gonna wait until next year and get a mid range or top of the range G5 PowerMac, but the G5 iMac has made me think twice about it. A G5 PowerMac would cost a small fortune, for power that I don’t really use, but it would last longer. But then I just love the new iMacs form, the idea of just having that sitting on my desk (I’m actually even thinking of the 20”, even though I have bad mouthed the 20” in the past for being a waste of money in the G4 days) rather than having a huge bloody great tower to find a home for, with wires running to monitors etc seems so much nicer. Plus the fact I could get a 20” 1.8GHz, with 1.25GB RAM, 160GB, SuperDrive etc for the same price as an entry level PM with no extras.

The only thing making me hold back is wondering if I will notice a difference going from my dual 1GHz G4’s, to a single 1.8GHz G5. Bear in mind, I really don’t do anything to strain the dual CPU’s at the moment (no 3D, video, heavy PS etc). So with this in mind do you think that a single 1.8GHz would appear faster for my needs (web, adium, occasional PS, iTunes etc)? Or, do you think I’d still be better off with a G5 PowerMac? Why?

Thanks for any input you can give!



BakedBeans
Sep 22, 2004, 03:00 AM
It’s been nearly 3 years since I bought my dual 1GHz G4 PowerMac (Quicksilver – 1GB RAM, 80GB+20GB, SuperDrive, GF4MX 64MB), and it has served me well, and honestly still does do everything I need with adequate speed. But, it’s getting close to that time when I want a new Mac again! Now, I was gonna wait until next year and get a mid range or top of the range G5 PowerMac, but the G5 iMac has made me think twice about it. A G5 PowerMac would cost a small fortune, for power that I don’t really use, but it would last longer. But then I just love the new iMacs form, the idea of just having that sitting on my desk (I’m actually even thinking of the 20”, even though I have bad mouthed the 20” in the past for being a waste of money in the G4 days) rather than having a huge bloody great tower to find a home for, with wires running to monitors etc seems so much nicer. Plus the fact I could get a 20” 1.8GHz, with 1.25GB RAM, 160GB, SuperDrive etc for the same price as an entry level PM with no extras.

The only thing making me hold back is wondering if I will notice a difference going from my dual 1GHz G4’s, to a single 1.8GHz G5. Bear in mind, I really don’t do anything to strain the dual CPU’s at the moment (no 3D, video, heavy PS etc). So with this in mind do you think that a single 1.8GHz would appear faster for my needs (web, adium, occasional PS, iTunes etc)? Or, do you think I’d still be better off with a G5 PowerMac? Why?

Thanks for any input you can give!

well ever since you gave me some advise about selling the powerbook and getting one i have looked into it a bit more... in your case i think you would see a good speed increase in your everyday apps and ive also heard that the gui reacts faster and feels even more snappy... and with tiger on the way i could only say it will get faster... i say if you dont need a powermac g5 for anything heavy then the 1.8 will be sickly fast... you know all this yourself but re-assurance over an expensive purchase isnt something we cant give, its you credit card.....

what do you really want????

it sound like you want the imac... but a powermac and a new 20" monitor would go down nice also...

i mean if you sold your dualie and screen then you could probably have a good chunk to go towards it..

edesignuk
Sep 22, 2004, 03:11 AM
This is the thing, I'd love a PowerMac G5, just to have a PowerMac G5, and to know the power is there, know what I mean? And I know it would also last me longer. But then I love the form of the iMac, and the price! Also because the price is lower I'd probably upgrade again sooner anyway, so that kinda balances out. Mainly I'm concerned of the speed difference I'd see between the dual G4, and the single G5. Which IMO should be quite significant as I know I don't use the dual G4's as they are meant to be used.

BakedBeans
Sep 22, 2004, 03:20 AM
This is the thing, I'd love a PowerMac G5, just to have a PowerMac G5, and to know the power is there, know what I mean? And I know it would also last me longer. But then I love the form of the iMac, and the price! Also because the price is lower I'd probably upgrade again sooner anyway, so that kinda balances out. Mainly I'm concerned of the speed difference I'd see between the dual G4, and the single G5. Which IMO should be quite significant as I know I don't use the dual G4's as they are meant to be used.

ive had a dual g5 1.8 with 2gb ram.... and i have to say.... i wasnt that impressed... im happier with my pb... the g5 was LOUD bigtime and although it was fast it didnt make me want to keep it... the price on the imac is amazing i would have though you were looking at £2k for the 20inch so for apple this price is great... and it would last a good while (if you can resist other new releases)

plus if your not using the dual 1ghz then why go for a dual g5 (there not the be-all) i would say going from a dual 1ghz (not used as a dual) to the imac is like going from an emac to a single 1.8g5 when they came out...

edesignuk
Sep 22, 2004, 03:36 AM
That's kinda what I'm thinking. Just wanted to get some other people thoughts on the matter, it's always good to have another input on decissions like this.

Diatribe
Sep 22, 2004, 03:39 AM
Barefeats has posted benchmarks of the new imac.
I posted it here. (http://forums.macrumors.com/showthread.php?t=89963)
It seems like it isn't that fast, not really faster than the G4 1,5 Powerbook and especially not than the 1,42Ghz G4 MP. So if you want to buy sth. that has power wait for the 3Ghz G5, which I think will definitely be out till march next year. It will serve you a lot better than the iMac in sheer power and will have a far longer life span.
If you want the all-in-one concept of the imac then go get it, but for me those benchmarks not being a lot better than a Powerbook's just killed it for me. For the regular consumer either upgrading from a imac G4 or being new to the mac platform I think it is a great value but for anyone wanting a "powerhorse" that will last them longer not just writing and surfing the net I think this is not it. Not until maybe the next rev. Who knows.

rdowns
Sep 22, 2004, 03:43 AM
That's kinda what I'm thinking. Just wanted to get some other people thoughts on the matter, it's always good to have another input on decissions like this.

Stop being such a weenie. Order the iMac, you know you want it. Otherwise you lose the right to post such a pretty 'tar. The pretty 'tar deserves the pretty computer.

As for speed, there are a bunch of benchmarks posted for the 1.8 in another thread. Users seem to agree that the 1.8 is very fast. As you don't exploit dual processors, seems like a no brainer.

Wish my 20" would ship already.

Oh yeah, stop being such a weenie and order it.

BakedBeans
Sep 22, 2004, 03:50 AM
Barefeats has posted benchmarks of the new imac.
I posted it here. (http://forums.macrumors.com/showthread.php?t=89963)
It seems like it isn't that fast, not really faster than the G4 1,5 Powerbook and especially not than the 1,42Ghz G4 MP. So if you want to buy sth. that has power wait for the 3Ghz G5, which I think will definitely be out till march next year. It will serve you a lot better than the iMac in sheer power and will have a far longer life span.
If you want the all-in-one concept of the imac then go get it, but for me those benchmarks not being a lot better than a Powerbook's just killed it for me. For the regular consumer either upgrading from a imac G4 or being new to the mac platform I think it is a great value but for anyone wanting a "powerhorse" that will last them longer not just writing and surfing the net I think this is not it. Not until maybe the next rev. Who knows.

to be honest i think that those test are a bit rubbish..... the 1.8 g5 with 1gb ram with smoke the powerbook..... in everyday use.... i would like to see them benchmarks... lke photoshop..or fcp or iphoto stuff like that..

edesignuk
Sep 22, 2004, 03:59 AM
Stop being such a weenie. Order the iMac, you know you want it.I know I do too :D
Otherwise you lose the right to post such a pretty 'tar. The pretty 'tar deserves the pretty computer.The 'tars will never go. But you're right, she would look good on the screen of that 20" :D
As for speed, there are a bunch of benchmarks posted for the 1.8 in another thread. Users seem to agree that the 1.8 is very fast. As you don't exploit dual processors, seems like a no brainer.I'm starting to think that too now more and more.
Wish my 20" would ship already.I've already emailed a couple of places asking what kind of lead times there are ;)
Oh yeah, stop being such a weenie and order it.:eek:

edesignuk
Sep 22, 2004, 04:00 AM
to be honest i think that those test are a bit rubbish..... the 1.8 g5 with 1gb ram with smoke the powerbook..... in everyday use.... i would like to see them benchmarks... lke photoshop..or fcp or iphoto stuff like that..Yeah me too. The iMac has a faster G5, faster HDD, faster BUS/RAM. How could it not be faster. And the second we see a 64Bit Tiger it'll be even more of a performance gap.

BakedBeans
Sep 22, 2004, 04:06 AM
Yeah me too. The iMac has a faster G5, faster HDD, faster BUS/RAM. How could it not be faster. And the second we see a 64Bit Tiger it'll be even more of a performance gap.

agreed, what are barefeets thinking posting tests like that...there normally quite good...

oh pressie for you
http://store.apple.com/Apple/WebObjects/ukstore.woa/91001/wo/An7FTEtkOOT82KzMibK1vDV2Mdz/2.0.9.1.0.6.3.


im thinking im going to get one... although i might wait for you to get one first... i like these damn things..

Enigma
Sep 22, 2004, 04:08 AM
Yeah me too. The iMac has a faster G5, faster HDD, faster BUS/RAM. How could it not be faster. And the second we see a 64Bit Tiger it'll be even more of a performance gap.

The Halo and UT2004 results will be because the Powerbook has a better graphics card than the iMac G5.

BakedBeans
Sep 22, 2004, 04:17 AM
The Halo and UT2004 results will be because the Powerbook has a better graphics card than the iMac G5.

and even then look at it

http://www.barefeats.com/image05/img5-ut4.gif


although im majorly pissed about them not having at least the 9600 in it... im thinking this card is not that bad after all... if it performs aswell as my radeon 9700m 64mb(or a little better/worse) then i will be happy...its fine.. plus i hate games...

edesignuk
Sep 22, 2004, 04:19 AM
im thinking im going to get one... although i might wait for you to get one first... i like these damn things..hehe, you looked around at all, got any idea how long we'd be waiting on them?

BakedBeans
Sep 22, 2004, 04:22 AM
hehe, you looked around at all, got any idea how long we'd be waiting on them?

have you tried micro anvika? cancom is saying 11 days.. not sure about the apple store....

edesignuk
Sep 22, 2004, 04:24 AM
One very important factor though, does anyone know if there is a dual screen hack for the 5200?

BakedBeans
Sep 22, 2004, 04:30 AM
One very important factor though, does anyone know if there is a dual screen hack for the 5200?

i know there is one...dont know if it works yet (but am looking..) and it has mirroring native... but not split screen

edesignuk
Sep 22, 2004, 04:39 AM
i know there is one...dont know if it works yet (but am looking..) and it has mirroring native... but not split screen
Split screen is very important for me!

Diatribe
Sep 22, 2004, 04:45 AM
I suppose you guys are right. The tests, on a second look, are maybe not the most representative. Oh well, it is a pretty nice looking computer. And having only one piece is definitely awesome.

BakedBeans
Sep 22, 2004, 04:51 AM
Split screen is very important for me!


lol if you tell me you love me infront of everyone... i will give you this hack and a picture of it working that i just got for you.....

come on... big me up...

edesignuk
Sep 22, 2004, 04:56 AM
come on... big me up...
mate, I beg of you! :D

BakedBeans
Sep 22, 2004, 04:58 AM
mate, I beg of you! :D

ahhh but do you love me????

lol... add me to you ichat so i can transfer it to ya...

http://www.isbrianworking.com/images/forums/spanning.jpg

http://www.allenshariff.com/images/dual_display.jpg

edesignuk
Sep 22, 2004, 04:59 AM
ahhh but do you love me????

lol... add me to you ichat so i can transfer it to ya...

algodden@mac.com
I can't, I'm at work :( :( Can you e-mail it to me? I'll PM you the address!

YOU'RE THE BEST! :p

Abstract
Sep 22, 2004, 05:06 AM
Well I say don't get it. Even if it's a tad bit faster, its not worth the price if its not much faster than your dual 1Ghz G4. I can't blame you for wanting it. I want to kiss it and hug it and snuggle it and caress it's sides and...... um....anyway, I have loved it since the introduction. However, I'm not going to cave. It sounds like you need it as much as I do. I guess sometimes its nice to buy something you "want" instead of "need," but this is one of those cases where you're going to think back and regret not getting something a bit faster, in case your needs change.

I'd like to buy a 1.33GHz 12" Powerbook, but hey, my 1GHz 12" PB is almost as fast. :p Sure, the faster bus speed, better video card, and brighter screen almost made me dump my loser PB and get the new sweet machine. Lucky I came to my senses and decided that such a small difference probably wasn't worth the extra £175-200 or so I'd lose from selling my current PB and buying the new one.

When the iMac is reported to be notably faster than what you have, then get one. Plus, its a rev A, and who knows what issues they may to sort out. While we usually tell people not to wait, I don't think waiting would be a bad idea in your case. But ordering the iMac anyway wouldn't be too bad, I guess. ;)

edesignuk
Sep 22, 2004, 05:16 AM
Thanks AL-FAMOUS, now the question is where did you find these? And where are the instructions on how to do it!?

edesignuk
Sep 22, 2004, 05:21 AM
Abstract, I know what your saying. But I also know that it will be faster, and because it's not as bigger of an investment as a PowerMac (it won't cost me an arm and a leg!), the fact that I don't actually need it badly makes the cost more acceptable.

BakedBeans
Sep 22, 2004, 05:24 AM
Thanks AL-FAMOUS, now the question is where did you find these? And where are the instructions on how to do it!?

you should be able to just open the .sit and then click on the script inside the file...

ive posted a thread about it here ( http://forums.macrumors.com/showthread.php?p=1047192#post1047192)

edesignuk
Sep 22, 2004, 05:27 AM
you should be able to just open the .sit and then click on the script inside the file...

ive posted a thread about it here ( http://forums.macrumors.com/showthread.php?p=1047192#post1047192)Brilliant! If I do end up ordering one, I'll thanks you again for this! :D

Savage Henry
Sep 22, 2004, 05:29 AM
When the iMac is reported to be notably faster than what you have, then get one. Plus, its a rev A, and who knows what issues they may to sort out. While we usually tell people not to wait, I don't think waiting would be a bad idea in your case.

As much as I feel like berating you for going all negative on an otherwise mac-phile-extreme thread by poisoning it with a level-headed rational approach to the purchase, I'm inclined to agree with you.

I'm torn because I love my FP 17" iMac ... and it arguably still meets my needs, but I would simultaneously mud-wrestle 3 of my mad Aunties if someone could justify to me why I really should purchase one now. And, against all my carnal instincts, I have decided to wait until Tiger comes out. By that time the top model may have been juiced with a bit more RAM and other model tweaks may have been ironed out.

edesignuk
Sep 22, 2004, 05:42 AM
Crap. Micro Anvika won't have any for 1-2 months!!!! :mad:

BakedBeans
Sep 22, 2004, 05:45 AM
Crap. Micro Anvika won't have any for 1-2 months!!!! :mad:

well 11 days from cancom.... have you tried apple store?

edesignuk
Sep 22, 2004, 05:47 AM
well 11 days from cancom.... have you tried apple store?
Who are cancom? No, haven't spoken to Apple...yet.

edit: never mind, got 'em :) http://www.cancomuk.com

caveman_uk
Sep 22, 2004, 06:28 AM
This is an interesting thread as I've been weighing up each side for when I upgrade. Like edesignuk I've got a Dual 1GHz PM (MDD not Quicksilver) and although I don't need to upgrade it'd be nice to ;) . I don't think I really need dualies either. I'm coming down towards an imac but I'll have to see one I think before I make up my mind. I've seen the G5 powermacs and they look unnecessarily huge for a machine with only one optical drive in it... I can probably wait until next year to buy anyway when the rev B and faster processors are in the imac...

Abstract
Sep 22, 2004, 07:31 AM
As much as I feel like berating you for going all negative on an otherwise mac-phile-extreme thread by poisoning it with a level-headed rational approach to the purchase, I'm inclined to agree with you.


Oh don't worry, I was only talking about edesignuk's case. He shouldn't get it, but despite the fact that you're in a similar situation, you should definitely go ahead and get it for yourself (as unconvincing as that sounds). ;)

Is there a John Lewis or something in Essex?

BakedBeans
Sep 22, 2004, 07:34 AM
Oh don't worry, I was only talking about edesignuk's case. He shouldn't get it, but despite the fact that you're in a similar situation, you should definitely go ahead and get it for yourself (as unconvincing as that sounds). ;)

Is there a John Lewis or something in Essex?

i doubt jl will have it in.....

edesignuk
Sep 22, 2004, 07:36 AM
Oh don't worry, I was only talking about edesignuk's case. He shouldn't get it, but despite the fact that you're in a similar situation, you should definitely go ahead and get it for yourself (as unconvincing as that sounds). ;)

Is there a John Lewis or something in Essex?
Why should Savage Henry get one and I shouldn't? he has a newer machine than me! (not as much power, but anyway...)

There's a John Lewis just the other side of the water in Bluewater shopping center, Kent. And of course in London.

ToddW
Sep 22, 2004, 07:43 AM
Get one, that is what I did. I had a 15" powerbook, but the iMac is the form factor I always wanted. And that 20" screen is great. I was doing some homework last night and the extra screen space was a god send. With the dual monitor hack working, what else could go wrong. You could get the 17" and use a second monitor or get the 20" and do the second monitor. I think the new iMac is fast, I am just getting to the point of doing some everyday things like ripping CDs, photoshop, iMovie, and iDVD and they all are performing well. The speakers don't sound that bad either, they just need a little more bass, and I think that can be solved with an iSub, or something like that. One more thing, it is a joy to look at and looks really good on a wood desk.

edesignuk
Sep 22, 2004, 10:32 AM
caveman_uk, I'm not as good as you. I've caved ;) myself. Just placed an order for a 20" stock config :eek: :D Should be here within the next 2 weeks, and I can't wait! Now to order some RAM....

http://upload.edesignuk.net/uploaded_data/smilies/cheering.gifhttp://upload.edesignuk.net/uploaded_data/smilies/cheering.gifhttp://upload.edesignuk.net/uploaded_data/smilies/cheering.gif

Savage Henry
Sep 22, 2004, 11:47 AM
Oh don't worry, I was only talking about edesignuk's case. He shouldn't get it, but despite the fact that you're in a similar situation, you should definitely go ahead and get it for yourself (as unconvincing as that sounds). ;)


Sir, that is exactly the kind of encouragement I need to absorb some of the slack that my credit card is unnecessariily harbouring right now...so desist with the temptation, please!

.... must ..... resist ... urges ..... must ... not .... buy ......

.... feeeling ..... weak ......

edesignuk
Sep 22, 2004, 11:50 AM
.... must ..... not ..... resist ... urges ..... must ... buy ......

.... feeeling ..... strong ......
Fixed :D ;)

Björn
Sep 22, 2004, 11:54 AM
PC magazine has reviewed the iMac G5 (today?) and they are giving it five out of five stars! PC Magazine review (http://www.pcmag.com/article2/0,1759,1648826,00.asp)

Found the news at MacWorld UK (http://macworld.co.uk/news/index.cfm?NewsID=9705)

Savage Henry
Sep 22, 2004, 12:01 PM
Fixed :D ;)

NURSE, the nasty men are toying with my brain .....

I'm gonna have to leave my office cos, man, the urge is really beginning to eat into me ....

edesignuk
Sep 22, 2004, 12:11 PM
I'm gonna have to leave my office cos, man, the urge is really beginning to eat into me ....Trust me, I know the feeling...and I snapped! :eek:

BakedBeans
Sep 22, 2004, 01:12 PM
oh well ******* it..... im gunna sell up and get one.... damn that nasty edesign fellow.....

edesignuk
Sep 22, 2004, 01:14 PM
oh well ******* it..... im gunna sell up and get one.... damn that nasty edesign fellow.....He's a real wanker isn't he? :D

<puts on essex cap and gets in citroen saxo> Go on my son! Go for it mate! Phat!</end talking like a di*k>

BakedBeans
Sep 22, 2004, 02:10 PM
He's a real wanker isn't he? :D

<puts on essex cap and gets in citroen saxo> Go on my son! Go for it mate! Phat!</end talking like a di*k>

whats happened to the swear word filter??? bollocks to it?

oh well... get yer Burberry cap on geeza.... us english are just so great...

Enigma
Sep 22, 2004, 02:24 PM
Managed to see an iMac G5 today (Scotsys on Great Western Road in Glasgow has them, if anyone's from the area and interested :) ) and it's thicker than I thought it would be. Still a nice design, but to be honest, I wouldn't get one until they upgrade the graphics card, it's just a bit too dated in my opinion.

I think it'd be great for my mum (a primary school teacher), as it's zero maintenance and with BT mouse and keyboard, there'd be one cable. No hassles. But any machine I've had has ended up having the hard disk, memory, optical drive etc. upgraded over the years, and for that reason I think I'd be more likely to get a G5 Powermac if I were looking at getting a desktop.

Just my 2c

(I, however, have a nice Powerbook arriving tomorrow, so I'm skint until about 2012 :) Maybe my research grant'll come in sometime this year and my Professor'll let me buy an Apple, but this will involve fighting with the (Windows-loving) departmental IT managers...)

rdowns
Sep 22, 2004, 02:42 PM
Split screen is very important for me!

Can you display porn on both at the same time? ;)

FuzzyBallz
Sep 22, 2004, 02:45 PM
Can you display porn on both at the same time? ;)
Well, isn't that the point of having multiple monitors?

edesignuk
Sep 22, 2004, 11:38 PM
Can you display porn on both at the same time? ;)I should bloody well hope so, why do you think I got the 20"!? :eek: :D

I'll be hooking up one of my current 18" LCD's as the second screen, so that'll be plenty of desktop space - 1680x1050+1280x1024 :D

QCassidy352
Sep 23, 2004, 01:22 AM
well congrats on your purchase, I hope you love it. :) But, I would be very surprised if it was a whole lot faster than your current machine. Remember when the single 1.6 and 1.8 powermacs came out and there were all those benchmarks comparing them to dual 1.25 and 1.42 G4s? Remember how the dual G4s ran about even and sometimes won?

Well, you have a dual 1 Ghz, not a dual 1.25 or 1.42, but do keep in mind that an imac G5 is not going to be as fast as a powermac G5 at the same clock speed due to the weak video card and scaled-back bus speed.

Anyway... don't mean to rain on your parade, just don't want you to get a nasty surprise when you get the imac and you're not blown away by the improvement over your quicksilver...

edesignuk
Sep 23, 2004, 01:27 AM
Well, you have a dual 1 Ghz, not a dual 1.25 or 1.42, but do keep in mind that an imac G5 is not going to be as fast as a powermac G5 at the same clock speed due to the weak video card and scaled-back bus speed.

But, my dual 1Ghz is a quicksilver = 100MHz BUS (SD100) = ***** slow. I would expect the jump in CPU+BUS speed+SATA drive to produce a notable difference, especially as as I have said before I don't utilize both processors 99% of the time with the kind of apps I use.

caveman_uk
Sep 23, 2004, 03:08 AM
But, my dual 1Ghz is a quicksilver = 100MHz BUS (SD100) = ***** slow.
If I recall the reports at the time there was very little difference between the MDD (DDR) and the Quicksilver (SDR) machines in terms of performance. I guess that an imac g5 WILL be faster than your (or my) powermac. Sadly I'm not wedged up enough to go for the dual 2.5GHz powermac - besides I'm moving my gear to a new room and the desk is smaller...ergo, need an imac (at least that's what I'm planning on telling the missus!)

edesignuk
Sep 23, 2004, 03:41 AM
Sadly I'm not wedged up enough to go for the dual 2.5GHz powermacWell exactly. If I had money to burn I'd get a decked out dual 2.5 in a heart beat, but I'm not, and it's not worth handing over an arm and a leg for something with so much power that realistically I just don't need...but it's nice to get a new Mac, so a 20" will do me nicely :D

BakedBeans
Sep 23, 2004, 04:16 AM
Well exactly. If I had money to burn I'd get a decked out dual 2.5 in a heart beat, but I'm not, and it's not worth handing over an arm and a leg for something with so much power that realistically I just don't need...but it's nice to get a new Mac, so a 20" will do me nicely :D

i was just think, this thread shows how far apple has come over the last little while..... the new consumer models are enough to satisfy all but the top pros.. you can easily run a business from the imac and the powerbooks now.... it wont be long (my guess is xmas 2005) and the pbs will ahve a g5

TheRat
Sep 23, 2004, 05:44 PM
I didn't read the thread, but this could apply to anyone who's making a tough decision:

- Find a coin, any will do
- Assign your choices to 'heads' or 'tails' (ie to buy mac or not to buy a mac)
- Flip 5 times

Why 5? Because before you get there you'll know what you want to do; You'll start thinking 'oh man i need another tails' or something like that. I can't remember the psychology behind it but it works.