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brandoncarr

macrumors newbie
Original poster
Nov 21, 2007
16
0
Hi All-

I recently purchased a 2006 Mac pro with 2x2.66 GHz Dual-Core Intel, and 12GB of RAM. It had the stock video card in it, and I upgraded it to the 5770 just this past week. I'm looking to upgrade the processors at some point, but right now I'm looking into upgrading my RAM. I want to max it out at 32GB. My question is about the bus speed. My system shows that I'm running 12GB at 667 MHz DDR2 FB-DIMM. What exactly determines bus speed? Is it something set by the CPU, by the motherboard, or by the RAM currently installed? It I were to pickup 32GB of RAM with 800 MHz, would it work, and would the bus speed be upgraded as well... Or how would that work?

Furthermore, what RAM upgrade would you recommend for my 2006 Mac Pro? Links would be appreciated. Looking for a good price too!

Thanks!

Brandon
 
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PowerPCMacMan

macrumors 6502a
Jul 17, 2012
800
1
PowerPC land
Hello,

In simplest terms the bus speed is controlled by the processors as well as the logic board. The Woodcrest family of Xeons support 667 Mhz DDR2 FB-DIMMS. While its possible to use 800 Mhz DDR2 FB-DIMMS, understand that you will NOT get 800 Mhz performance out of the memory since the architecture only supports 667 Mhz DDR2 FB-DIMM memory. In most cases, 800 Mhz will just downclock itself to 667 Mhz as this is the MAX speed the memory will run at.

Only the Harpertown Mac Pro or Mac Pro 3,1 runs at full 800 Mhz bus DDR2 memory due to the memory controller, processors, and logic board.

The rule of the thumb is 2006-2007 Mac Pros will only run at 667 Mhz, later Mac Pros run at 800, and of course, the 2009-2010 Mac Pros use an entirely different architecture + the memory runs at either 1066 Mhz DDR3 or 1333 Mhz DDR3 and this is controlled by the processors.

To be on the safe side, unless 800 Mhz DDR2 FB-DIMMS are readily available while 667 Mhz might be harder to get, then go with 800 Mhz, knowing full well that the memory will down clock to 667 Mhz.

As far as what memory to recommend, OWC is a good Mac dealer for Mac Pro memory, but understand that compared to DDR3 memory, DDR2 FB-DIMMS is very expensive due to the fact DDR3 is more widely in use these days and DDR3 a lot faster.

I hope I was clear.


Hi All-

I recently purchased a 2006 Mac pro with 2x2.66 GHz Dual-Core Intel, and 12GB of RAM. It had the stock video card in it, and I upgraded it to the 5770 just this past week. I'm looking to upgrade the processors at some point, but right now I'm looking into upgrading my RAM. I want to max it out at 32GB. My question is about the bus speed. My system shows that I'm running 12GB at 667 MHz DDR2 FB-DIMM. What exactly determines bus speed? Is it something set by the CPU, by the motherboard, or by the RAM currently installed? It I were to pickup 32GB of RAM with 800 MHz, would it work, and would the bus speed be upgraded as well... Or how would that work?

Furthermore, what RAM upgrade would you recommend for my 2006 Mac Pro? Links would be appreciated. Looking for a good price too!

Thanks!

Brandon
 

JesterJJZ

macrumors 68020
Jul 21, 2004
2,443
808
It's pretty expensive indeed. I'm still on a 2006 and holding out for the next MacPro. Got SSDs and new processors and feeling pretty good. Going from my current 16GB to 32GB will cost over $700. I could sell my 16GB afterwards, but I'd barely recoup half that.
 

PowerPCMacMan

macrumors 6502a
Jul 17, 2012
800
1
PowerPC land
Best advice I can give for those who still love using their 2006 Mac Pros: Get a few SSD drives and that will compensate for the slower memory, since SATA mechanical drives are the bottleneck.

667 Mhz DDR2 is simply not cheap these days and I assume 800 Mhz fares no better either. I saw the prices on OWC's website. DDR3 is so much cheaper while FB-DIMMS for 2006,2007, and 2008 Mac Pros is much higher. Assess your needs and application use to determine how much memory you will need.

You have heard it before even in the PowerPC days: More memory or max memory = FASTER MAC. True, but today with SSD drives the speed of even those defeat that equation.
 

brandoncarr

macrumors newbie
Original poster
Nov 21, 2007
16
0
Best advice I can give for those who still love using their 2006 Mac Pros: Get a few SSD drives and that will compensate for the slower memory, since SATA mechanical drives are the bottleneck.

667 Mhz DDR2 is simply not cheap these days and I assume 800 Mhz fares no better either. I saw the prices on OWC's website. DDR3 is so much cheaper while FB-DIMMS for 2006,2007, and 2008 Mac Pros is much higher. Assess your needs and application use to determine how much memory you will need.

You have heard it before even in the PowerPC days: More memory or max memory = FASTER MAC. True, but today with SSD drives the speed of even those defeat that equation.

Thank you for your advise sir. It's much appreciated! I was looking at macsales/OWC, and I did a MyOWC lookup, and they didn't seem to have any SSD's for my 2006... Is there one that you might recommend? Thanks again!

Brandon
 

GermanyChris

macrumors 601
Jul 3, 2011
4,185
5
Here
To push to 32Gb here has an ebay price of 768 euro unless you desperately need 32Gb then I'd stick with 16 which is less than half. For SSD's I am the dissenter on this and most forums I actually like OCZ drives because I've had no failures and have nothing but positive things to say about there support but I think I'm the only one on the internet. I currently use an Agility 3 in the my MP and a Vertex + in the MBP.
 
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