[hojo]

I just bought a Mac Pro from B&H (delivers today) - 4-core 3.0 ghz/X1900 with one gig of RAM. I want to upgrade the RAM to 8 gig. From Crucial, I note that 8 gigs of 2-gig x4 is $840 vs 8 gigs of 4-gig x2 at $1749.

Looking at RAM from Crucial -- my question..assume that I pull the the two OEM 512's...in getting to 8 gigs there some substantial advantage to using as few DIMMs as possible? IOW, is it worth twice the cost having two of the eight RAM sockets filled for $1749 as opposed to 4 of them filled for $840? Is heat an issue? Timing? Other reasons that fewer DIMMs would be substantially better? Worth the $800+? extra?

And...if I use 2-gig DIMMs x4 (my preference, obviously), I'll still have 4 open sockets in the 2nd riser. Any problem with slapping the OEM two 512 meg DIMMs in that configuration for a total of 9 gig RAM?

[roller]

I found a pretty good article about the Mac Pro RAM situation over at Macworld. It doesn't directly address your specific questions, but I think you can draw a reasonable conclusion from it. Here is the article:

MacWorld RAM Article

For my pocketbook, I don't see spending double unless your ultimate goal is to max out your RAM to the 16 gig limit.

[sknapp351]

I just received my Mac Pro yesterday and am wondering much the same. If I want 4GB of ram, am I going to see any benefit of 4 x 1GB or 2 x 2GB? ( other than price ) I just went from a G5 with 8GB or ram to a Mac Pro with 1GB, that was an eye opener.
SAm

[mduell]

The Mac Pro doesn't support 4GB modules (Apple crippled it for reasons unknown; the Xserve does support them), so 4x2GB is your only choice.
Also, you want to put the 2GB modules on both cards (on the inner [closest to the logic board] two slots of each card). You can put the 2x512MB together on either card in the outer slots.

Originally Posted by sknapp351 

I just received my Mac Pro yesterday and am wondering much the same. If I want 4GB of ram, am I going to see any benefit of 4 x 1GB or 2 x 2GB? ( other than price ) I just went from a G5 with 8GB or ram to a Mac Pro with 1GB, that was an eye opener.
SAm

4x1GB will be faster (twice the bandwidth) than 2x2GB today. But if/when you go to 8GB, 4x2GB is faster (lower latency) than 8x1GB.

[sknapp351]

Originally Posted by mduell 

4x1GB will be faster (twice the bandwidth) than 2x2GB today. But if/when you go to 8GB, 4x2GB is faster (lower latency) than 8x1GB.

Thanks. I think that 5 GB will suffice for some time. I will want to put the 1GB dimms closest to the logic board right?
Sam

[roller]

Originally Posted by sknapp351 

I just went from a G5 with 8GB or ram to a Mac Pro with 1GB, that was an eye opener.
SAm

Just curious: In what sense was it "an eye opener"?

[mduell]

Originally Posted by sknapp351 

Thanks. I think that 5 GB will suffice for some time. I will want to put the 1GB dimms closest to the logic board right?

Yes.

Originally Posted by roller 

Just curious: In what sense was it "an eye opener"?

Slower than molasses in January?

[sknapp351]

Originally Posted by roller 

Just curious: In what sense was it "an eye opener"?

Originally Posted by mduell 

Slower than molasses in January?

Pretty close. It is usable, but I am used to having 15 or so widgets running and my fiancé ( it's actually her computer ) will often have up to ten apps running when she works. Ram wasn't something we thought about. Now page outs are constant. I will be ordering the new ram pretty quick.
SAm

[someone]

Originally Posted by mduell 

The Mac Pro doesn't support 4GB modules (Apple crippled it for reasons unknown; the Xserve does support them), so 4x2GB is your only choice.

Are you sure about this? OWC advertises a 32GB max for the Pro, and there are some screenshots of it working out here...
32GB Mac Pro (using 4GB FB-Dimms)

[mduell]

Interesting, Crucial is selling them too. I was misinformed.

[mavherzog]

Nice. I am planning buying myself a disgustingly overspec'ed Mac Pro once I return home from Iraq. I had already planned on maxing the RAM out at 16GB...Now I guess I'm going to have to double the insanity.

(planning on spending around $15k...which includes 4x750GB hdd's, and two 30" displays. looks like I can still hit that general price with 32GB of ram from OWC)