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RAM speeds in 4,1 Mac Pro

s-hatland

s-hatland

macrumors regular
Original poster
Feb 4, 2014
150
98
Hey everyone,
I've got a 4,1 Mac Pro (2009) and am needing to upgrade the RAM. I've only got 8GB in there now, which is paltry for my photoshop needs. My plan is to buy three 16GB sticks spread out over the time it takes to save for each one. However, looking down the road, I'm eventually going to upgrade the processor (as well as bumping the firmware to 5,1 for 6-core options and 1333mhz RAM speeds). Here's my question: Can I buy a 1333mhz stick of ram now? Will it run at 1066 until I upgrade the processor/firmware? Also, I understand that when using 16GB sticks, they need to be the same/matched part numbers. If I buy each of these, say, 6 months apart, will that be okay?

Any help and advice is much appreciated!
 
s-hatland said:
Hey everyone,
...Can I buy a 1333mhz stick of ram now? Will it run at 1066 until I upgrade the processor/firmware? Also, I understand that when using 16GB sticks, they need to be the same/matched part numbers. If I buy each of these, say, 6 months apart, will that be okay?
Click to expand...


You can run 1333mhz ram at 1066 - I did that for a while until upgrading my cpu.

You don't need to 'match' the memory. You shouldn't try unbuffered and registered dimms together - i know that doesn't work from experience. My suspicion is mixing ECC and non-ECC won't work, but it might boot with everything in non-ECC mode. Mixing speeds might work, though I'm guessing everything would run at the slowest speed.

But trying to match vendor or part numbers isn't necessary at all. I had a mix of different sizes in my 4,1 for a while, though now just using 3x8GB ECC/registered.
 
You can use 1333 RAM now, but they will only run at 1066.

Mixing RAM is actually OK, I've try 2xstock 2G ECC RAM + 2xKingston 4G non-ECC RAM. No problem at all, but of course ECC will be disabled.
 
thank you both for the info! looks like i'll be ordering today. as far as mixing sizes, i always knew it was okay to mix, say, 4 and 1 or 8gb sticks together, but for some reason or another, i thought i remember reading somewhere that 16gb sticks only play nice with other 16gb sticks. the vendor issue was more what i was worried about since (eventually) i'll be maxing it out @ 3x16gb.
 
The 16G sticks might be ECC/registered-only, and won't play nice with unbuffered sticks. I'd guess your current ram is ECC/unbuffered...

But I can't afford 16G sticks, so have no experience with them personally.:)
 
well that makes sense. thanks again.

regarding being able to afford the big sticks. i look at it this way. i've got 8gb now. i "have" to at least go to 16gb, whether by 2x8gb or one 16gb. 2 eights are $192 and 1 sixteen is $215. when spending nearly $200 dollars, a $23 difference seems moot when factoring that i can expand the RAM further with 16gb sticks...

just me though. unless you've got the scoop on some super cheap 8s.
 
I found 3x8GB ECC/registered dimms on ebay for $150. Granted it was used, but price was hard to resist.

For the new prices you're showing though I'd go 16G over 2x8G. I thought when i looked i was seeing way more for the 16G sticks, but I was looking mostly at 3x kits so might have missed some deals.
 
It's best to match RAM if you can. The CPU in a 4,1 or 5,1 has three channel memory, so it's best to fill slots 1, 2, and 3 and leave slot 4 MT. And Yes, 1333MHz RAM will run just fine at 1066MHz.

Lou
 
On my 4,1 I was using 1066 ram and after the 5,1 firmware hack it now runs at 1333. Honestly the difference between the two speeds is unnoticeable, just go with the big sticks and ignore the speed.
 
^^^^I disagree. 1066MHz and 1333MHz RAM prices are pretty much the same for new DIMMs. Why not use the fastest speed the machine and the CPU will support? Makes no sense to me why you would choose slower RAM.

Lou
 
well, the first stick is on it's way. thanks again for all of your helps. I also got a SATA 3 ssd under the presumption it was backwards compatible. I realize it will only run at SATA 2 speeds but in case I ever need to move it, sorta like the ram, may as well buy the fastest.

just please no one tell me the ssd won't work :)
 
s-hatland said:
well, the first stick is on it's way. thanks again for all of your helps. I also got a SATA 3 ssd under the presumption it was backwards compatible. I realize it will only run at SATA 2 speeds but in case I ever need to move it, sorta like the ram, may as well buy the fastest.

just please no one tell me the ssd won't work :)
Click to expand...

your new SSD will work just fine :)
 
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