What do you mean 10 gigs/6 sticks of ram will slow me down???

[CalfCanuck]

I read in a thread here that for the fastest performance, you should have 8 identical ram sticks, and the second choice is to have 4.

My Mac Pro is coming with two sticks (1GB each) and I ordered another four (2 gb each) for a total of 10 gigs of ram.

Am I really going to take a performance hit here? Would I be better off pulling the two 1 GB sticks and just having 8 GB of ram instead of 10 GB?

You will get a performance hit of around 10% or so.

I'm going to quote Barefeats:

"I tested the 10GB scenario... With that config I get the same fast memory fill rates in Xbench as I did with just the four 2GB FB-DIMMs (two on each riser, slots 1+2). "

Why are people implying crazy things like "using the extra RAM will give you a 10% speed hit"? I am constantly amazed at some of what I read on here.

Even barefeats, who started this entire uproar about the performance penalty, EXPLICITLY said he found no performance difference using 10 GB (as the OP asked about) compared to 8 GB.

People need to get real about what the ACTUAL, not theoretical, bottlenecks to typical computing are. The discussion about RAM configurations looks at memory speed tests only, but unless you are a very small minority (running a render farm, etc) this is rarely YOUR bottleneck. Far more likely is a lack of total memory and caching to the HD, which is a HUGE speed hit to computing.

 

[JesterDev]

If someone can just answer this for me I can drop this whole topic and get on with life.

2GB x 2 & 2GB x 1 (Stock)

or

2GB x 4 & 2GB x 1 (Stock)

I can save about $33 by going with the 1st option. Which is better?

--

Coming from 22 years of PC's so I've never run into such issues.

 

[orpheus1120]

I think you mean

2GB x 2 & 1GB x 2 (Stock) = 6GB

or

2GB x 4 & 1GB x 2 (Stock) = 10GB, since the stock comes with 2 x 1GB.

I would choose neither. I would prefer

2GB x 4 & 1GB x 4 (adding 2 more 1GB).

BUT if you really have to choose between the two, obviously I would choose 10GB over 6GB.

 

[Mr.PS]

I just ran Xbench before and after I installed the 2 x 2gb sticks from OWC. The results are near identical, give or take a few. This leads me to believe 6gb (2 x 1gb and 2 x 2gb) is a very good setup!

Before:
Results 181.23
System Info
Xbench Version 1.3
System Version 10.5.1 (9B2117)
Physical RAM 2048 MB
Model MacPro3,1
Drive Type WDC WD3200AAJS-41VWA0
Memory Test 181.23
System 215.28
Allocate 345.66 1.27 Malloc/sec
Fill 170.22 8276.43 MB/sec
Copy 193.51 3996.79 MB/sec
Stream 156.49
Copy 157.75 3258.34 MB/sec
Scale 158.07 3265.64 MB/sec
Add 155.31 3308.52 MB/sec
Triad 154.87 3313.09 MB/sec

After:
Results 199.89
System Info
Xbench Version 1.3
System Version 10.5.1 (9B2117)
Physical RAM 6144 MB
Model MacPro3,1
Drive Type WDC WD3200AAJS-41VWA0
Memory Test 199.89
System 279.47
Allocate 322.17 1.18 Malloc/sec
Fill 232.30 11294.94 MB/sec
Copy 300.67 6210.23 MB/sec
Stream 155.58
Copy 156.79 3238.53 MB/sec
Scale 157.50 3254.00 MB/sec
Add 154.37 3288.36 MB/sec
Triad 153.73 3288.58 MB/sec