Installing 2+4 GB RAM vs 2x2 GB

On OWC's site they say my 20" iMac can handle up to 6GB of RAM. It is my understanding that Mac's generally prefer matched pairs of RAM so I'm wondering if I might see only a marginal improvement in performance over my current 2 x 2GB configuration, or will adding another 2GB really get me the full benefit of 6GB?

The reason I ask is that I'm anticipating upgrading my hardware (more RAM, possibly an SSD) to better handle Lion when it comes out this summer. I'm wondering if my money might be better spend just switching to an SSD and leaving the RAM at 4GB. I'm anticipating Lion to be even more of a RAM hog than Snow Leopard.

I will offer my experience as a possible solution to your question.

I have a 2010 27" iMac i3, and I bought two 4 GB Ram from OWC, I put these two sticks in the two bottom ports of my iMac (in addition to the two "stock" 2 GB sticks)...I immediately noticed a substantial difference. I did a test right before adding the ram which consisted of running 5 Movies simultaneously, opening word, mail, itunes, safari, and final cut. When I opened the programs, they all opened slow and the movies all stopped flowing, instead ran very poorly.

After I added the ram, I noticed a substantial increase in production under the same test. The movies ran more fluently and there was not much of a "lag" when I opened the programs.

Although it is a different generation iMac, I hope this answers your question.

I would venture to say the Cost/benefit will be very bad if you consider the the SSD option. The ram option will be much cheaper.

I'm no expert, but no matter where the OS (Lion) is stored, HHd or SSD, you will need ram to run it. I understand an SSD to make boot time faster. I think the actual operation of the SSD will lean towards ram and the CPU. I would buy ram, cheaper and I think you wiuld notice more of a difference with the Lion update rather than the SSD.
I doubt they have released recommended specs for lion yet. Check those out before you buy anything.

Go with the Mercury Extreme SSD from OWC. It is the best upgrade you can make and if you use intensive apps, also upgrade the memory also.

so did you end up buying 6GB or 4 GB? im in a same boat. which one should i buy? :S

I too added 8GB of RAM for a total of 12GB and my iMac LOVES it. As Bentharbour said, however, you do have a different generation of iMac though.

To clarify, the heart of my RAM question is whether or not my computer will care if it sees a mis-match of one 2GB stick and one 4 GB stick instead of a matched pair (2x2GB, which I currently have) and not reap the full benefit of the 6GB combo. If that were the case, I'd skip the extra 2GB of RAM and just upgrade my HD to an SSD.

50voltphantom said:

To clarify, the heart of my RAM question is whether or not my computer will care if it sees a mis-match of one 2GB stick and one 4 GB stick instead of a matched pair (2x2GB, which I currently have) and not reap the full benefit of the 6GB combo. If that were the case, I'd skip the extra 2GB of RAM and just upgrade my HD to an SSD.

Click to expand...

If that is the case, you would be buying a 4GB stick anyway...why would you take 1 2GB stick out and put in a 4 GB? Why not just add the 4 GB stick and have a total of 8 GB?

Maybe you have plans for the other 2GB, or maybe I missed something I don't know.

Re: SSD vs. RAM

Ttaylor394 said:

I would venture to say the Cost/benefit will be very bad if you consider the the SSD option. The ram option will be much cheaper.

I'm no expert, but no matter where the OS (Lion) is stored, HHd or SSD, you will need ram to run it. I understand an SSD to make boot time faster. I think the actual operation of the SSD will lean towards ram and the CPU. I would buy ram, cheaper and I think you wiuld notice more of a difference with the Lion update rather than the SSD.

Click to expand...

Yes and no...

While you're right that upgrading the RAM is the more cost-effective option out of the two possible upgrades, and the one that will provide more noticeable immediate improvements, if you really want your Mac (or PC, for that matter, this applies to all computers) to fly it is worth upgrading to an SSD.

Not just because of better boot & App launch times, but because of virtual memory. OSX (and Windows too) uses a certain amount of the HDD to supplement the RAM, in the case of Snow Leopard I think it's in the region of 10GB. That's why you should always leave at least that much space unused - as "breathing room" for the OS - on your primary Macintosh boot drive.

While upgrading from an ordinary hard disk to a solid-state drive won't increase the size of your virtual memory - Snow Leopard / Lion / whatever will still only allocate the same 10GB for VM - what it will do is speed it up (the same as replacing the RAM in your Mac with the same amount, but supporting a higher frequency).

The read/write speed of SSDs is significantly higher than ordinary HDDs (even 7200rpm "high speed" drives), meaning that OSX will be able to access the virtual memory significantly faster; and so speed-up the system as a whole.