[ug.mac]

Hi guys,

I want add some memory to my PowerMac G5 1.6Ghz, I can get some cheap Sumsang 512MB DDR400 memory @ CAD$105, 2GB costs $420 (maybe less); 1GB memory they selling for CAD$360, $720 total for 2GB. So I should go 4 memory sticks in 512MB each or get two 1GB each? Will I notice any difference on performance?


Thanks a lot.

uG.mAc.

[Catfish_Man]

The performance will be the same with 2x1024 vs. 4x512, so the only reason that the 1024 chip is better is future expansion.

[ug.mac]

Thx, Catfish_Man,

But I think 2GB memory should be good for least 2 years, so it won't be a problem for me.

[chasg]

I went with 4 x 512Mb modules myself, that gives me my total 2.5Gb of RAM, and still leaves a slot free for future expansion (I almost bought 2 x 1Gb modules, just by reflex, until I realised I could get what I wanted for much cheaper and still be able to load more in later)

By the time I'll be able to buy more RAM, I'll need it 'cause Photoshop 12 will just have come out and will require a 6 processor Mac with 1/2 terabyte of holographic RAM, LOL!

[Axo1ot1]

LOLZ@@!!!!!!!!!!!!@!

[gururafiki]

It seems that 2x1gig sticks would be faster than 4x512mb sticks because there are less sticks for the computer to access when using the memory. Although I doubt the speed would be very noticeable...

[SafariX]

Two bye 1 point oh is your best bet for future expandibility.

[tooki]

Originally posted by gururafiki:
It seems that 2x1gig sticks would be faster than 4x512mb sticks because there are less sticks for the computer to access when using the memory.

That's not how it works. In fact, the opposite is true. Remember how in most G5s, RAM must be installed in pairs? That's because those models access two RAM modules at once, allowing much higher RAM throughput. If there were one memory controller per RAM slot, the effect would be greater (the G5s have one memory controller per RAM bank).

In this case, because either way it's going in in pairs, performance will be identical. There is absolutely no speed penalty for using multiple modules. To the system, there is no difference.

tooki

[gururafiki]

Originally posted by tooki:
That's not how it works. In fact, the opposite is true. Remember how in most G5s, RAM must be installed in pairs? That's because those models access two RAM modules at once, allowing much higher RAM throughput. If there were one memory controller per RAM slot, the effect would be greater (the G5s have one memory controller per RAM bank).

In this case, because either way it's going in in pairs, performance will be identical. There is absolutely no speed penalty for using multiple modules. To the system, there is no difference.

tooki

Is this the same for G4's? A friend of mine always said his G4 started quicker than my powerbook based on the fact that he had less RAM modules in it.

[Superchicken]

Your G4 owning friend was stupid

His tower would have started up faster because it had a faster HD than the laptop which saves power by having a slower HD.

My 1Ghz PowerBook has a 4200rpm HD, I put a 60 gig HD in my iMac 333Mhz a while ago, and it starts up faster than my PowerBook.

[tooki]

Originally posted by gururafiki:
Is this the same for G4's? A friend of mine always said his G4 started quicker than my powerbook based on the fact that he had less RAM modules in it.

Some Macs (such as the 85/86/95/9600) use something called memory interleaving, which increases performance by about 10% if RAM is installed in matched pairs. Other machines, like the 61/71/8100, require RAM in matched pairs because of bus width, but still only use one memory bus. The middle and high-end G5 models use RAM in matched pairs because of its dual memory controllers, which allows access to both banks at once.

In all G3 and G4 models, there is in no case ANY speed penalty for having the RAM exist in more or less modules. If you install, say, 512MB of RAM, it doesn't matter if it's 4x128 or 1x512 -- it takes the computer the exact same time to test the RAM, and it is all accessed as one unified chunk of RAM.

tooki

[gururafiki]

Thanks tooki & Superchicken. My friend, who works at Kinkos is the "Fix It" guy for this region, will freak when he sees this thread, which is exactly why I am going to point him to it...

[Catfish_Man]

Actually, if the system runs a ram test at startup, more ram could slow it down. However, the number of sticks it's in would be irrelevant.

[tooki]

Originally posted by Catfish_Man:
Actually, if the system runs a ram test at startup, more ram could slow it down. However, the number of sticks it's in would be irrelevant.

Umm, yeah. The question wasn't about the total amount of RAM. Obviously it takes longer to test more RAM. The question was whether it made a difference how the RAM is configured, and the answer to that is no.

tooki