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4x1GB verses 2x2GB
- Thread starter speekez
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i would too.....i say keep it. like someone else said, if you have to take it in for repair, you'll have to have it
Those are both great places to purchase memory upgrades. I bought
2 gigs from Datamem for my iMac and 2 gigs from OWC for my MacPro
and they both work perfectly.
[/two cents]
some interesting info on this page:
http://diglloyd.com/diglloyd/free/MacPro/memory.html
scroll down to the "mac pro memory bandwidth chart"
The 4x2GB seems to be the strongest combo.
http://diglloyd.com/diglloyd/free/MacPro/memory.html
scroll down to the "mac pro memory bandwidth chart"
The 4x2GB seems to be the strongest combo.
So if i get the 4x1GB set then i shouldn't be using the stock 2x512mb set, correct? I'm looking to make a ram purchase soon so this clarified would help.
Actually am kind of lost, cause I haven't received my mac pro so I have no reference but I will try and educate myself on it after work today.
thanks
Actually am kind of lost, cause I haven't received my mac pro so I have no reference but I will try and educate myself on it after work today.
thanks
So if i get the 4x1GB set then i shouldn't be using the stock 2x512mb set, correct? I'm looking to make a ram purchase soon so this clarified would help.
Please read what osx-linux wrote the last couple of pages. He answered pretty much all of our questions.
Yes, read the darn chart.
2x2GB + 2x512MB is better than 4x1GB, the boost by trying for quad channel and dropping the extra 1GB is negligible -- but if you need that extra 1GB, the penalty may be HUGE.
The VM Memory manager is a major bandwidth penalty, sort of like speeding along at several GB/s and slamming into a HD's slow MB/s wall.
If I hold off putting the 2x512MB of RAM in until later; would I still put the 4x1GB of RAM into the same slots?
2x1GB sticks in slots 0 and 1 of riser A
and
2x1GB sticks in slots 0 and 1 of riser B.
Here is the ultimate Mac Pro configuration guide (courtesy of peloche on discussions.apple.com):
http://peloche.smugmug.com/photos/91752872-O.jpg
Transcend memory?
This quad channel stuff is interesting and exactly what I've been trying to understand. I am looking to add more memory to my recently ordered Mac Pro. I was thinking of adding 4x1 gb sticks. Anyone have any experience with Transcend memory? This looks like a bargain!
http://www.newegg.com/Product/Product.aspx?Item=N82E16820208199
This quad channel stuff is interesting and exactly what I've been trying to understand. I am looking to add more memory to my recently ordered Mac Pro. I was thinking of adding 4x1 gb sticks. Anyone have any experience with Transcend memory? This looks like a bargain!
http://www.newegg.com/Product/Product.aspx?Item=N82E16820208199
Some of the wording is confusing me. You say lowest slots on the risers, do you mean lowest in ordinal sense (slot 1 and 2 are lower than 3 and 4??).
I have my original 2x512 in the top riser, in the first two slots. Then in the bottom riser, I have 2x2GB, for a total of 5 gigs.
Which sticks are running at full bandwidth, and which are not? And also, you say if I were to get 2x2GB more and put them in riser B with the other 2x2, that riser full of 8GB would run at full bandwidth, and the top riser with 2x512 would run at half?
I am not understanding this. It sounds like I shot myself in the foot getting 2x2GB, unless I intend to put 4x2GB in the bottom riser, and 4x1 in the top riser?
Are you essentially saying that, if you have more than 2 sticks total, they need to be on alternating risers, but to get full bandwidth, you have to have at least 6 sticks, with one full riser?
Each riser card has a 128bit lane to it. if you are using both of them at the same time you are essentially using a 256bit lane. But if one riser card has more ram then the other, once the card with the lesser memory is full, the rest of the "data" will have to go to the riser with the more memory on it, reducing it back down to a 128bit lane for that data.
So as long as you have 2 sticks on each riser you can use quad channel but if on riser has less memory not all of the memory will have "quad channel".
say u have 2 by 1GB on one riser and 2 by 512 on the other..and the computer needs to put 750 MB of data on..by what i am told..half would go to one riser and half on the other. essentially using a 256 bit lane bc it is using 2 128 bit lanes. now to put 2.5GB of data only 1GB can go on one riser. and 1.5 GB will have to go on the other. so the ".5" of the 1.5GB will be sent on a single 128 bit lane. This is why it makes a very small difference..but also such a big difference. the larger the gap of the amount of memory on the risers the more of a difference it will make. of course..thats assuming I am correct in eeverything I have just said.
Brad
So as long as you have 2 sticks on each riser you can use quad channel but if on riser has less memory not all of the memory will have "quad channel".
say u have 2 by 1GB on one riser and 2 by 512 on the other..and the computer needs to put 750 MB of data on..by what i am told..half would go to one riser and half on the other. essentially using a 256 bit lane bc it is using 2 128 bit lanes. now to put 2.5GB of data only 1GB can go on one riser. and 1.5 GB will have to go on the other. so the ".5" of the 1.5GB will be sent on a single 128 bit lane. This is why it makes a very small difference..but also such a big difference. the larger the gap of the amount of memory on the risers the more of a difference it will make. of course..thats assuming I am correct in eeverything I have just said.
Brad
I'm Confused About The Speed Difference
This chart shows all the different ways one can and should populate the Mac Pro memory risers with all the different stick configurations for every possible RAM total. Are you saying not to follow this chart and only use matching pairs of RAM sticks in each riser to maintain maximum speed?
For example, I am receiving a previously owned Mac Pro this morning that has 5GB of RAM in it with the two 512 sticks it came with plus four 1GB sticks the previous owner added to it. Should I pull the 512 sticks and add four 2GB sticks? That's an extra $600 I'd rather not put into this Mac. But adding two 2GB sticks for only $300 more is not too much more expense if I would benefit from that move. I guess I should sell all 6 sticks and replace it all with four 2GB sticks for maximum speed. But I don't know if I'll benefit from 8GB of RAM vs. 4GB of RAM that much. My inclination is to just leave it at 5GB the way it is.
How much can I sell 512MB & 1GB sticks anyway?
Below the chart are what I see as my choices to use what I get plus two 2GB sticks if necessary or majorly advantageous.
This chart shows all the different ways one can and should populate the Mac Pro memory risers with all the different stick configurations for every possible RAM total. Are you saying not to follow this chart and only use matching pairs of RAM sticks in each riser to maintain maximum speed?
For example, I am receiving a previously owned Mac Pro this morning that has 5GB of RAM in it with the two 512 sticks it came with plus four 1GB sticks the previous owner added to it. Should I pull the 512 sticks and add four 2GB sticks? That's an extra $600 I'd rather not put into this Mac. But adding two 2GB sticks for only $300 more is not too much more expense if I would benefit from that move. I guess I should sell all 6 sticks and replace it all with four 2GB sticks for maximum speed. But I don't know if I'll benefit from 8GB of RAM vs. 4GB of RAM that much. My inclination is to just leave it at 5GB the way it is.
How much can I sell 512MB & 1GB sticks anyway?
Below the chart are what I see as my choices to use what I get plus two 2GB sticks if necessary or majorly advantageous.
Attachments
That's why I'm also confused. If I buy 2x2 to add to my existing 2x512, would I be using the full 256 bit addressing or would it be better to get 4x1 to add to 512x2!?
From how I understand this whole mess..if u added 2x2 and used the 2x512 you WOULD use 2GB of quad channel and 3GB of dual channel. So if you use more than 2GB you will pry be slightly slower than if you had quad on all of it..but that is the route I plan to take when I get a Mac Pro soon..hopefully after they update.
so essentially you have to have matching risers to get "quad channel" access? Whatever is in the top, the same has to be in the bottom? Just amount of raw gigabytes, or the number of sticks also?
this sounds like black magic.
this sounds like black magic.
I agree. And why buy expensive from a bad reputed place when you can get same as OEM memory from Crucial at $380 for 2x2GB http://www.crucial.com/store/listparts.aspx?model=Mac Pro (4-core)&pl=Mac Pro&cat=RAM
Here's Crucial Memory against Apple OEM = http://web.mac.com/tribe3/iWeb/Site/Library.html
I'm a little confused though. Wouldn't those 512 sticks in configuration 1 remove some bandwidth from the B riser overall? With the 2x1GB, can it run at full bandwidth if the 512 sticks are on there too?
if i may attempt to answer you question...
your talking about the 4x1GB and the 2x512 right, the 2 512 sticks would only be used if the 4 1Gb sticks are full. so 4 Gb would be able to run at 256 bit access before the 2 512's would be used, then anything that the 512s have would run at 128 bit. Which is STILL faster then using VM. so you better off having the extra GB if u need it.
I think for now I"m going to settle on 4x1 to go with my 2x512. I can't imagine needing more than 8gb rams, I don't do anything intense like video - just an occasional video once or twice a year.
My final question is this: any one have any experience with Transcend ram for the Mac Pro: Transcend 1GB DDR2 667 (PC2 5300) ECC Fully Buffered Memory for Apple Mac Pro - it's about $70 a stick. Not looking to be cheap necessarily but I am looking for the most bang for my buck.
My final question is this: any one have any experience with Transcend ram for the Mac Pro: Transcend 1GB DDR2 667 (PC2 5300) ECC Fully Buffered Memory for Apple Mac Pro - it's about $70 a stick. Not looking to be cheap necessarily but I am looking for the most bang for my buck.
I have the 2.66 Mac Pro with 2GB (4x512), (It came that way when I bought it from MovieCutter). Memory prices have become more realistic as of late. If I wanted to buy 4GB how should I buy it? Here are questions I need to resolve:
Should I keep the original Apple 4x512mb or sell it?
If I keep the 4x512mb, should I buy the 4x1GB or 2x2GB.
I want to be able to get the best bandwidth and optimal usage of the RAM. Whatever I need to do to make this happen I am game. Should I just use the 4GB (4x1GB or 2x2GB) and forget about using the 512mb modules?
Sorry if my questions might be a little redundant, I am just trying to get all my questions that I have swirling around in my head out so that I can make the best decision.
Your thoughts would be helpful.
Should I keep the original Apple 4x512mb or sell it?
If I keep the 4x512mb, should I buy the 4x1GB or 2x2GB.
I want to be able to get the best bandwidth and optimal usage of the RAM. Whatever I need to do to make this happen I am game. Should I just use the 4GB (4x1GB or 2x2GB) and forget about using the 512mb modules?
Sorry if my questions might be a little redundant, I am just trying to get all my questions that I have swirling around in my head out so that I can make the best decision.
Your thoughts would be helpful.