Is there a performance hit for mixed DIMMS?

profBIll

macrumors newbie
Original poster
Mar 13, 2007
10
0
2Gb in my SR MBP is proving to be a little less that I need, especially for parallels. I was thinking of buying just a single 2Gb stick, replace one of the 1Gb sticks, to get a total of 3Gb.

My question was whether there is a performance hit to have mixed DIMMs in the system? Anybody seen a performance loss with 3Gb of memory? Any help appreciated.

>>>bill<<<
 

mad jew

Moderator emeritus
Apr 3, 2004
32,199
6
Adelaide, Australia
It almost certainly won't be a performance hit if you're finding 2GB isn't enough RAM. The benefits of having enough RAM versus having slightly faster matched chips are much greater. :)
 

CanadaRAM

macrumors G5
Your hit for giving up dual-channel will be about 6%
Your gain on having more RAM will depend on how you use the machine --

if you are regularly exceeding 2 Gb RAM now and paging out to the hard drive, then you might see as much as 20% gain.

If you operate now entirely within 2 Gb and close programs religiously when not in use, and your don't see any PageOuts, then you may not see any gain from the extra 1 Gb.
 

docc

macrumors 6502
Jun 19, 2007
256
18
Miami
I'm using 2.5GB RAM on my macbook and the performance is MUCH higher in comparison to stock 1GB RAM it came with.
 

vicious7

macrumors 6502a
Jul 16, 2007
818
0
Jacked into the net...
I also started getting pageouts with all the software I was running concurrently so I went up to 4Gigs. And I'm now much happier. OWC has some good deals on matched sticks.
 

profBIll

macrumors newbie
Original poster
Mar 13, 2007
10
0
That is exactly what I wanted to know. Thanks very much to everyone who chimed in.

>>>bill<<<

Your hit for giving up dual-channel will be about 6%
Your gain on having more RAM will depend on how you use the machine --

if you are regularly exceeding 2 Gb RAM now and paging out to the hard drive, then you might see as much as 20% gain.

If you operate now entirely within 2 Gb and close programs religiously when not in use, and your don't see any PageOuts, then you may not see any gain from the extra 1 Gb.