PDA

View Full Version : Specific Ram Types For Macs



macanyday
5th May 2005, 08:19 PM
Hi all,
I want to discuss ram types.
I see loads of cheap ram available out there but is it compatable with the mac.
For instance:
A G5 needs PC3200 DDR 3.3volt ram.
Iíve heard PC ram is 2.6volts.
Does this work on a G5?
These PC stores etc have no idea about this issue if they only deal with PCís
They donít know what voltage their ram is.)
Is there a way to tell? Hereís an example.
I spoke to msy (http://msy.com.au) and they have no idea what there ram is.
They have a 1G PC3200 DDR400 Hyundai chip so I asked for codes on the chip sticker and it had:
Hynix 515AA HY5DU12822BT-D43
& KOR2.8DDA067
Tried to locate info based on that and a google actually led me to here. Where someone said Hynix Ram is mac compatable in their G5. Can we confirm this and what other brands are Mac comapatable?

any info would be much appreciated.
ta,

Confuscious say: he who stick his d#*k in peanut butter must be f*#king nuts.

titan44
5th May 2005, 08:31 PM
Places like MSY, Comp World .e.t.c. are only good if you know exaclty what you want, they are NOT a place to go to add to you IT Knowledge, that said, more often than not, you won't find stuff cheaper anywhere else.


I would advise not to put any cheapo yum cha ram in your mac, it's just not worth it, go with a reputable brand ( matched pair, like Geil, Crucial or even Kingston ) and you should'nt have any probs.

And yeah, good quality PC ram works ( same, same ).

macanyday
6th May 2005, 10:17 AM
Thanks for that,
I will look for a matched pair.

purana
6th May 2005, 10:45 AM
Originally posted by macanyday@May 5 2005, 08:19 PM
Hi all,
I want to discuss ram types.
I see loads of cheap ram available out there but is it compatable with the mac.
For instance:
A G5 needs PC3200 DDR 3.3volt ram.
Iíve heard PC ram is 2.6volts.
Does this work on a G5?
These PC stores etc have no idea about this issue if they only deal with PCís
They donít know what voltage their ram is.)
Is there a way to tell? Hereís an example.
I spoke to msy (http://msy.com.au) and they have no idea what there ram is.
They have a 1G PC3200 DDR400 Hyundai chip so I asked for codes on the chip sticker and it had:
Hynix 515AA HY5DU12822BT-D43
& KOR2.8DDA067
Tried to locate info based on that and a google actually led me to here. Where someone said Hynix Ram is mac compatable in their G5. Can we confirm this and what other brands are Mac comapatable?

any info would be much appreciated.
ta,

Confuscious say: he who stick his d#*k in peanut butter must be f*#king nuts.
It appears PC manufacturers typically have mainboards default settings at running memory @ 2.6v. However most ram these days, ie. PC3200 (DDR400) is typically requires 3.3v (and if I was to use this chip in my PC @ the DDR400 speed) then I would need to jumper my PC to supply 3.3v to the ram.

If I was to run that DDR400 @ 2.6v then it wouldn't be running at DDR400 speed any more (aka 400mhz). It would be quite lower.

When it comes to picking ram, you want to of course confirm its the right size (number of pins) and then confirm its speed rating. If machine requires PC3200 (DDR400) then this is the minimum speed you should buy. Buying a PC2700 (DDR333) means its going to cause problems, as this chip is only rated to max speed of 333Mhz. And to run @ 400Mhz it would need to be overclocked (and overclocked memory = problems).

The memory you found @ MSY is the same memory people have been using in Mac Mini's.

When you say does it work in a G5, which model you referring too? Imac G5? Powermac G5? Give us a little more details, so we can determine what minimum speed memory the model requires to determine if the PC3200 is suitable.

purana
6th May 2005, 10:46 AM
Originally posted by titan44@May 5 2005, 08:31 PM
Places like MSY, Comp World .e.t.c. are only good if you know exaclty what you want, they are NOT a place to go to add to you IT Knowledge, that said, more often than not, you won't find stuff cheaper anywhere else.
Grr, I hate those people in front of me @ MSY who ask all these questions. Like man if they want pre-sales service, goto Harvey Norman. Meanwhile the rest of us in the queue just want to walk in and say I want this and this. Pay and walk out.

macanyday
6th May 2005, 12:10 PM
to answer your question. I am referring to a G5 tower. Ė G5 Tower Oringinal single 1.8ghz, FX5200 (64mb), 4xDVDR, 1.5gb ram (2x512mb & 2 x 256mb) Tiger OS

And yes I agree with you in regards to the counter hold ups. thats why Iím asking you guys. how else do you learn?

Byrd
6th May 2005, 12:33 PM
Originally posted by iodine@May 6 2005, 10:45 AM
It appears PC manufacturers typically have mainboards default settings at running memory @ 2.6v. However most ram these days, ie. PC3200 (DDR400) is typically requires 3.3v (and if I was to use this chip in my PC @ the DDR400 speed) then I would need to jumper my PC to supply 3.3v to the ram.

If I was to run that DDR400 @ 2.6v then it wouldn't be running at DDR400 speed any more (aka 400mhz). It would be quite lower.
That's not correct; It's difficult to explain but all PC memory found on standard consumer desktop PCs uses 3.3V SDRAM (available in SDR, DDR and DDR2 variants), while there is 5V DIMM RAM used in some PowerMacs and PC servers (5V is much rarer).

The RAM is powered on a 3.3V rail of the computer's power supply but the actual RAM chips are fed another voltage, usually around 2.5 - 2.8V to run at it's factory specification, for example with most variants of DDR400 RAM. Some RAM chips love a high voltage - allowing it to run at much lower latencies, eg. Winbond BH5 chips have fairly poor CAS ratings at a default voltage of 2.6V, but often run @ CAS 2-2-2 when fed 3.0V+. However, supplying a higher voltage of RAM can smoke the chip and increase heat output.

RAM voltage can be adjusted on an overclocking friendly PC motherboard, but not a Mac. So in other words, get the best quality RAM you can afford for your G5, as it'll have a lower RAM latency than cheaper generic RAM, thus providing more memory bandwidth and performance.

JB

mwot
6th May 2005, 12:44 PM
I have found this from Streetwise (http://www.streetwise.com.au/memory.php) to be handy when selecting/shopping for RAM for my mac.

jobe
6th May 2005, 02:45 PM
Originally posted by iodine@May 6 2005, 10:45 AM
If I was to run that DDR400 @ 2.6v then it wouldn't be running at DDR400 speed any more (aka 400mhz). It would be quite lower.
That's not entirly correct. Think of it as a CPU. You can run your CPU at rated speed at any voltage. However if the voltage is too low or too high it will not function properly (at it's rated speed).

Virtually all DDR ram on the market today is 3.3v except for a few rated higher (very rare as Byrd has said and very much more expensive).

macanyday. When buying new ram for you mac. There are only a few things you need to consider.

1) what type of ram. SD or DDR

2) what form factor. DIMM (used by most PC and mac desktops) or SO-DIMMs (used by most PC and Mac laptops and a few desktops like the g4 imacs).

3) What speed. G5 powermacs take PC3200 DDR. You can buy any DDR (NOT DDR2) PC3200 or higher and it will be compatible. So PC3500 or PC4000 (again, NOT DDR2) etc will all work and run at PC3200 speed. Though These faster sticks tend to be more expensive and are aim at overclockers so they can run a higher FSB. You CANNOT however buy slower sticks like PC2700 or pc2100. This may seem obvious but it has been done.

4) the max supported memory in each DIMM. Something like 1 or 2gb for the G5 powermacs, so nothing to worry about.

oh and 5) ECC or not (Error correction code built in). If it has ECC it will say it and it will be more expensive. If it doesn't have ECC then it most likely won't mention anything about it or at most say non-ecc.

So essentially from this you can gather that any DDR non-ECC PC3200 stick that can be picked up from any PC or Mac store will work (in theory). However as has been said time and time again, really elcheapo sticks can cause you problems, I cbf to explain the main reason why right now unelss you want?

Also... may I PLEASE ask that you read some of the dribble I've put in this sticky (http://forums.appletalk.com.au/index.php?showtopic=6983). I went to all the trouble to type it up and no-one has read it. Poor little me ;)

EDIT: if you want a further (perhaps confusing) outline of G5 powermacs ram then I suggest taking a look at the apple developer's notes on it here (http://developer.apple.com/documentation/Hardware/Developer_Notes/Macintosh_CPUs-G5/PowerMacG5/4Expansion/chapter_5_section_2.html#//apple_ref/doc/uid/TP40002012-CH208-TPXREF102). I hesitate to post this though because sometimes it's very ambiguous and can be confusing if you don't understand much about ram in the first place.

calebd
27th May 2005, 09:52 AM
hey, I have read everything here about this but still can't seem to get an answer, I have a dual 2ghz G5, will a 1024MB 128X64 High Density DIMM Configuration 184 pin stick of ram work? I know I they need to be matched pairs, but will they work? please, anyone??? from what I can tell this ram runs at 2.6V if that helps....????

jobe
27th May 2005, 02:59 PM
so you have 2 512mb sticks or a single 1024mb stick? If it's the first and they are matching pairs (ie- same manufacturer and model) and not ecc or registered then yes.

mvjs
27th May 2005, 04:56 PM
Well, depend on a number of factors, including how many slots, if you already have ram in there, e.g. if you already have a 512stick in there, buy another 512 stick, would be more affective then going out and buying a gig stick. A lot of extra cash, for not a huge benefit.

Currawong
27th May 2005, 05:12 PM
You can stick any standard PC3200 (400Mhz) DDR RAM into a G5 and the computer will boot. Just don't use "generic" RAM as it's crap. In G5's, RAM is installed in matched pairs. That's the short answer.

calebd
27th May 2005, 07:09 PM
ok, I have a G5, got it standard with 512 ram, I am looking at buying 2GB of ram, 2 x 1gb sticks, will high density work, or should I get low dencity, high density doesn't work in many PC m/b's so just wondering which to to get, it's non-ecc Geil that I am looking at getting? anybody know if high density will work in a G5? as nobody seems to have any posts anywhere I assume that they do, but thought I should check before spending the cash

Atomic
27th May 2005, 08:27 PM
ok my $0.02c

I bought 4 sticks of Hynix 1GB RAM from MSY Sydney for $132 each. I can confirm that they are working flawlessly in my DP2.5GHz G5.

I have no idea but I am certain they are CAS3. Its nearly impossible finding anything faster in 1Gb sizes and as has been mentioned above, would be horrendously expensive.

jobe
27th May 2005, 09:36 PM
calebd: I'm fairly confident it will work. this lot (http://eshop.macsales.com/item/Samsung/3200DDRSAM1G/) sell high density dimms specifically for powermac G5s.

ShaneHm2
29th May 2005, 03:44 PM
all ddr non ecc and non registered ram is rated at 3.3volts unless over volted