06-12-2007, 12:28 PM

I have 2 GB Mac Pro with 1 GB of RAM and I really need a memory upgrade.

So I went to ebay and found Optival memory much cheaper then the original Apple one.

The problem is that Optival has a more expensive memory that includes their Hyperformance technology. Is it worth investing 30% more in price to this kind of RAM in my computer? And I think my original memory inside the Mac is slower then the new one and it will drag the performance down, so I should remove it and let only the better memory in.

Please let me know what to do.

06-12-2007, 02:04 PM

If you don't want to pay Apple prices, then I would suggest checking out a third party retailer, such as Newegg or Crucial for your RAM. eBay can be a total pain when it comes to hardware purchases.

Stuff like Hyperformance and all that nonsense is just that, nonsense. It's all a marketing gimmick to get you to pay more for effectively nothing

06-12-2007, 02:12 PM

Thanks.

I read is better to have the same size modules in your Mac. I would have 2x512 MB and 2x2 GB. Is it OK? Would it affect the system performance?

06-12-2007, 02:19 PM

The Mac Pro uses FB-DIMMs, which need to be installed in pairs. So if you need 2GB, you'll need to install two 1GB modules.

06-12-2007, 03:16 PM

I meant having 2 modules of 512 MB each and 2 modules of 1 GB each. I heard this configuration would slow the system.

06-12-2007, 07:27 PM

No that would not affect your system, since you would have 1.5GB in each bank of slots. I don't if you would know a different if the memory were not in pairs. Apple suggest that you install in pairs for better memory management. So two of where ever you put in will be okay.

06-13-2007, 10:50 AM

I may be misunderstanding what you are saying, but memory must be installed in pairs so bank A would have 2Gb in it and bank B would have 1Gb in it.

If you were to try putting 1.5Gb in bank A and 1.5Gb in bank B, I suspect the system wouldn't even start. I recommend NOT doing this

Joe

Originally Posted by rman

No that would not affect your system, since you would have 1.5GB in each bank of slots. I don't if you would know a different if the memory were not in pairs. Apple suggest that you install in pairs for better memory management. So two of where ever you put in will be okay.

06-13-2007, 01:38 PM

There are eight slot, I believe in the Mac Pro. So you can put 1GB in slot A1 and 512MB in slot A2, for 1.5GB in slot A. You will need to then place 1GB in slot B1 and 512MB in slot B2, to have a matched set.

You must put a memory stick in slot A and B for the system to boot up. You can put 1GB in slot A and 512MB slot B and your system will boot. But for better performance the matched pairs is better (ie. 1GB in both lost A and B).

06-13-2007, 04:58 PM

Originally Posted by rman

There are eight slot, I believe in the Mac Pro. So you can put 1GB in slot A1 and 512MB in slot A2, for 1.5GB in slot A. You will need to then place 1GB in slot B1 and 512MB in slot B2, to have a matched set.

You must put a memory stick in slot A and B for the system to boot up. You can put 1GB in slot A and 512MB slot B and your system will boot. But for better performance the matched pairs is better (ie. 1GB in both lost A and B).

No. I mean, I'm sure it may work, but it isn't the way to go.

Keep the memory in balanced pairs.

Each riser has two channels running to the memory controller. Channel 0 is DIMM 1 and DIMM 3 on the top riser, Channel 1 is DIMM 2 and 4. You want these channels to match, the memory control wants these channels to match.

So, abc should put his new 1Gb DIMMs in Slots 1 and 2 on the top riser. Channel 0 will be 1GB+0GB=1GB, as will Channel 1. Matched!

Then abc will put the original 512Mb DIMMs in Slots 1 and 2 on the bottom riser. This turns on Channels 2 and 3, taking advantage of the Mac Pro's quad channel memory controller. Channels 2 and 3 should be balanced like 0 and 1 above.

abc, by using both risers, you are taking advantage of all four channels, which is (on paper) faster than just loading up one riser and only using two channels. Plus, DIMMs 1 and 2 on each riser connect directly to the high-speed bus, DIMMs 3 and 4 routed through DIMMs 1 and 2 first.

abc, how can tripling your RAM slow the system? There may be more optimum combination of chip types and sizes, but all of that is inconsequential compared to the boost you'll get from having more RAM.

Personally, I would buy from someone who gives a warranty and will be easy to reach if there are problems. Crucial is tops. OWC is lower cost, yet reputable. I find it hard to believe Optival has come up with a way to make their memory 30% faster without any competing product from the larger dealer\rs.

06-15-2007, 11:55 AM

wyattoons, regarding tripling the ram, I read a thread here saying that having different size double modules would affect the system performance.

I checked with Crucial and they do not guarantee the heat sinks on their memory modules are always fin like. Apple do recommend flat heat sinks on FB-DIMMS.

So I found another online store: MacRAMDirect.com. Did anybody buy from them?

Another option would be newegg.com, but they don't ship to Canada.

Thanks for OWC. I didn't know about them.

06-15-2007, 01:01 PM

Make sure to do yourself a favor and really shop around for memory prices. They will vary from vendor to vendor, and from reseller to reseller.

06-15-2007, 02:29 PM

Originally Posted by abc

wyattoons, regarding tripling the ram, I read a thread here saying that having different size double modules would affect the system performance.

Keeping that extra 1 Gb of RAM in there will negate just about any adverse effects.

I have heard questions on mixing sizes, but am not convinced, more importantly, it is not cost effective to use all 512's, nor will it make adding more RAM easier later on. And by keeping the 512's in there, you get to take advantage of the quad channel memory controller and you get an extra Gb of RAM.

The important thing is to always keep the higher capacity DIMMs on those inside slots where they have a straight shot to the controller.

I also thought about my original answer and I don't see any reason to switch the 512s from the top riser to the bottom. Just adding the new DIMMs on the bottom riser opens up the extra channels and the system should perform identical regardless of which pair is on which riser.

Have you looked at Neweggs prices? They are the highest of the bunch, I guess they got looked in to a wholesale price and now they can't drop the price like Crucial, OWC and others have in recent months.