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Grenadier

macrumors regular
Original poster
Nov 12, 2006
106
0
Crucial states that it is possible to put non-ECC RAM into a ECC system (Eg: The Mac Pro).
Do you think this is true ? Does this mean I can just go with the stock RAM, and then later replace it myself with Standard and rather cheap DDR2 instead of expensive ECC FB-DIMM modules ? (Albeit I will have to get rid of the stock RAM when replacing since apparently, you cannot put ECC and Non-ECC in a system)
Could someone confirm/deny this for me ?
 

mkrishnan

Moderator emeritus
Jan 9, 2004
29,776
15
Grand Rapids, MI, USA
Apple has a site that specifically lists non-ECC as okay for almost every Mac EXCEPT the Mac Pro... Also other sites have discussed in some detail the need for the specific FB modules with the big heatsinks. Anyway, I'd be fairly careful, even though Crucial is usually good about identifying what you need....
 

slughead

macrumors 68040
Apr 28, 2004
3,107
237
crucial has been messing up a lot recently on the mac pros--shipping the wrong ram, normal heatspreaders (no big heat sinks as in the pics), etc.
 

omfgninja

macrumors member
Aug 9, 2006
42
0
Crucial states that it is possible to put non-ECC RAM into a ECC system (Eg: The Mac Pro).
Do you think this is true ? Does this mean I can just go with the stock RAM, and then later replace it myself with Standard and rather cheap DDR2 instead of expensive ECC FB-DIMM modules ? (Albeit I will have to get rid of the stock RAM when replacing since apparently, you cannot put ECC and Non-ECC in a system)
Could someone confirm/deny this for me ?

wont work
FB-DIMM's work in different ways than standard memory. I believe all thouse RAM sticks have an extra memory microcontroller to have it work in serial, or something.
I forget extactly, but im almost 100% sure that you can only use FB-DIMMs in a Mac Pro.
 

ChrisA

macrumors G5
Jan 5, 2006
12,623
1,763
Redondo Beach, California
.... Standard and rather cheap DDR2 instead of expensive ECC FB-DIMM modules ....

Lots of technical reasons why this will not work. The first thing you will notice if you try is that the Mac Pro uses 240 pin RAM while the standard DDR2 is 200 pins so it will not physically fit into the slot (unless you use a really big hammer which or course might void the warranty.)

In general, in the past, in some non-Apple computers you could put non-ECC ram into machine designed for ECC RAM. The way this works is they made "fake" ECC RAM. ECC RAM had a bit that sent either "good" or "bad" and they simply hard wired it to always send "good" even i the RAM was not. On PCs there used to by "Fake parity" RAM that would compute rather then store the parity bit. Basically the same idea -- send "good" no matter what.
 

Grenadier

macrumors regular
Original poster
Nov 12, 2006
106
0
Aha,
I see.

Do you think though that by any chance Fake-ECC RAM would work ?
And would it even be worth it ? (By that I mean, would it be THAT much cheaper ?)
 

swiftaw

macrumors 603
Jan 31, 2005
6,328
25
Omaha, NE, USA
Aha,
I see.

Do you think though that by any chance Fake-ECC RAM would work ?
And would it even be worth it ? (By that I mean, would it be THAT much cheaper ?)

If you're spending all that money on a Mac Pro I wouldn't risk performance by using dodgy RAM, isn't it kind of like buying a Ferrari then using low-octaine gas?
 

tyr2

macrumors 6502a
May 6, 2006
827
217
Leeds, UK
Aha,
I see.

Do you think though that by any chance Fake-ECC RAM would work ?
And would it even be worth it ? (By that I mean, would it be THAT much cheaper ?)

I'd be amazed if 'Fake-ECC' even existed in the FB-DIMM format.

Also I don't think there's a Non-ECC version of FB-DIMMs even if you wanted to go that way. At least I've not come across any.

It's a Mac Pro you just have to fork out the extra costs for FB-DIMMs there's nothing you can do about it really.
 

Grenadier

macrumors regular
Original poster
Nov 12, 2006
106
0
Understood. Its a pity, but Ill just have to live with it.
Well, thank you for your time gentlemen.
 
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