512 + 1GB =???

[se7enbelow]

Please help me understand this? It's my understanding that unmatched pairs will take a speed hit, but how much would these configurations vary?

-512RAM(single slot)
-512 + 1GBRAM (unmatched pairs)
-1GB(single slot)

It's my assumption that the 1.5GB will be the fastest, but I'm not sure, I get mixed signals around here about the details of unmatched pairs. Would I be better off just running the single slot 1GB?

(This is also for iMac 1.83Ghz Duo, but this is the best forum I've found for these things)

((I'm trying to figure this out because I'm not sure if I want to commit to buying 2GB just yet, I'd like to start with adding 1GB))

Tanks in advance

[iMav]

[247 Photography]

Normally, 512 MB or 1 GB would comprise two memory modules. You can't buy it new that way, or with unpopulated memory slots.

[MiniMoe]

Given that you have an Intel iMac with a single 512MB SODIMM, I'd try to buy a similar one pulled out of another Intel iMac. That would be a cheap way to get you to 1GB of 2 matched sticks, which should be more than enough for now, especially considering you have dedicated video RAM, where Minis have to use some of the system RAM.
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[ecking]

I don't see why an intel imac or mbp would need the matched pairs. They've got dedicated gpus so it's not like they need dual channel anything.

Infact at the apple store the other day their core duo mini was using 1.5gb if ram and it didn't feel slow at all even though they weren't doing dual channel to maximize the gpu.

So why would unmatched pairs on somethign with it's own gpu (imac, mbp) make a difference?

[MiniMoe]

[iMav]

[offabroadway]

It's written somewhere in the Apple website that switching to unmatched pairs when you upgrade your memory drops your throughput from 10.6Gb/s to 5.2Gb/s. So you get your memory, its just twice as slow.
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[se7enbelow]

First, thanks for all the contributions folks, I'm learning a lot hanging out around here.

[MiniMoe]

New iMacs (and MacBook Pros) with dedicated video cards come with one single 512MB SO-DIMM. When you Build To Order an iMac with 1GB of memory, you can chose to get it as one single 1GB SO-DIMM or two 512MB SO-DIMMs. The price either way is the same $100.

New Minis (and MacBooks) with integrated video come with two 256MB SO-DIMMs for 512MB. Since the integrated video uses the main memory, the usage of it is much higher than on the iMac and MBP. The processor speeds are also 82-83% that of the iMacs, so it's more important to optimize speed in another area, memory access.
_________________
Moe
1.66GHz Core-Duo Mini, 2GB/120GB, Apple 23" Cinema HD Display
Apple Wireless Keyboard & Mouse, Apple iSight Camera
Apple USB Modem (for faxing), Bose Companion 2 Speakers
2.0GHz white MacBook 1GB/80GB

[247 Photography]

My mistake. I didn't notice that this was an iMac question. This a Mac Mini forum.

[se7enbelow]

[Tenex]

[se7enbelow]

Actually I think I did post this in "Upgrades" originally. Someone did move it here, it was my mistake...

[Susurrus]

Okay, a couple of things. First, 247Photo is wrong and Tenex is right.

Second, having a matched pair will be faster than not having a matched pair, from a RAM bandwidth perspective. iMav hit this issue right on the head.

[quote=iMav]None of three configurations take advantage of the dual channel architecture, so given the choice, go with 1GB + 512MB.[/quote]

None will be slower than the other as none have a matched pair for dual channel. So more RAM will therefore be better.
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