Vendor (OWC) comments about Mac Pro Memory
The following is from Larry at Other World Computing (OWC). I’ve broken it up into a question and answer format for readability. Statements by OWC are theirs alone, and have not been independently verified by DIGLLOYD INC.
DIGLLOYD: How do the OWC modules compare to the “NetList” modules, especially in light of the higher price of the NetList modules?
In a word - today - there is no difference in terms of performance and OWC's quality is equal to if not HIGHER than that which Netlist currently provides.
One other significant difference is that Netlist is now building their Mac Pro FB-DIMMs in China. I wasn't aware of that change until an explanation they gave concerning a delay had me asking for that confirmation.
OWC modules are built at a contract partner right here in the USA on a state of the art line we have full specification control over and just a short trip for us address in person any details with our productions. This production control is also why OWC was the first out there in the Mac community (among other things ) to have stock of the new DDR3 1GB 1066MHZ PC8500 modules (the same day apple released in fact) for the latest new MacBook and MacBook Pro systems.
Being more than just a reseller brokering parts from anywhere - OWC is in a advantageous position to both provide competitive prices as well as the highest quality when it comes to the Apple memory upgrades.
DIGLLOYD: That’s “today”, was the situation different when I first wrote All About Mac Pro Memory?
When the first Mac Pro 667MHz models were released in August 2006, we were the first to offer (outside of Apple) memory upgrades for these new systems. Apple had kept the spec tight, but Netlist was a supplier to Apple and our relationship with Netlist enabled us to also have access to the same Apple certified line that was being supplied to Apple. It would be a several weeks before heat sinks that would meet Qualify by Apple would become available... That didn’t stop a lot of the RAM guys out there from saying that JEDEC Spreader equipped modules (talking the type that go into Xeon rack servers including the current Xserves) were ok which definitely caused hard to short term, and if not, long term reliability of the systems installed into.
(DIGLLOYD: no kidding, I tried those Xeon-style FB-DIMMS and ECC errors cropped up like kudzu).
For two decades now, OWC has been a provider of Apple Spec and qualified memory upgrades. We maintain a full test lab of all the Apple models we sell memory for and have an ongoing test program that ensures full compatibility and reliability. This goes well beyond just testing for memory function as memory might be just fine – but be it an SPD programming issue or a problem with the die or device type used, doesn’t mean it will work correctly in a Mac. Our testing lab is there for quality control above all since we have strict control over memory modules that are contract manufactured for our company with the specific specifications and requirements necessary for proper operation in Mac models.
DIGLLOYD: So what happened in the 2006-20076 timeframe with some of the memory problems we’ve heard about with Mac Pros?
In late 2006 , OWC attained it’s own heat sink solutions and began offering it’s own qualified modules for the Mac Pro. The only difference between the Netlist and the OWC were the heat sink (OWC’s actually was like the one most commonly found on modules in Mac Pro as Apple primarily used the Netlist modules for overseas) and that as they were not being used by Apple, they weren’t subject to nor eligible for Apple certification – the SAME, if not more stringent testing is actually done on EACH Mac Pro module we build compared to what can be called certified – so in no way is our Apple Qualified module of a lesser grade or quality than the Netlist parts.
In early 2007 – OWC was the first company to report a compatibility problem with the NEC AMB that Apple had on it’s list of qualified components. The issue only materialized with the modules actually going into the Xserve, but it was a spec issue that resulted in Apple DROPPING qualification for the NEC chipset officially in April of 2007 for both Xserve and Mac Pro FB-DIMM modules. You might remember the concern about the new April 2007 Mac Pros not being able to use the prior Mac Pro 667MHZ memory as Apple had made such indication. Since Apple didn’t differentiate modules by NEC or IDT AMBs prior to the issue being noted, they couldn’t say what prior memory met the revised spec or didn’t – although any Apple modules with the IDT AMB (which was by far the majority) were A-OK.
Well – OWC customers had no worry as used IDT for our modules and continue to use IDT EXCLUSIVELY today for the AMB. Currently only the IDT AMB is approved by Apple for the Mac Pro FB-DIMMs and while there are lower cost alternatives that seem to work just fine – OWC strictly adheres to the Apple qualified to insure our customers don’t have any problems, period. Some might remember back in 2000 when Apple released a firmware update that resulted in a whole bunch of memory to stop working.... The memory that stopped working was product that was not correctly programmed and while prior to the firmware change worked, it was responsible for system instability that was being blamed on Apple’s OS when it was really timing issues with the memory. Long story short – OWC received significant positive press after that firmware update with Pioneer Press newspapers who were really happy to tell the world that while the OWC memory continued to work great, they had other supplier provided memory that was no longer operating cause it wasn’t spec. OWC has a long history of providing the right, proper spec memory for systems – not just stuff that seems to work but that could really be a time bomb waiting to go off.
DIGLLOYD: What about the 2008 Mac Pro memory modules?
In Early 2008 – OWC was the VERY FIRST company to have the new PC6400 Mac Pro 800MHZ modules available. While we’d intended to offer Netlist along side, Netlist was not selected by Apple as a supplier this time and although we’d also given orders to them in addition to having starting building our own modules well ahead of the Apple introduction – Netlist was not able to fill orders for months to come due to internal supply issues. The parts were not in very good supply needed for these modules and Netlist had not planned appropriately.
Bottom line is that there is really no compelling reason to purchase Netlist modules over our OWC brand. We use components to the Apple Qualified Spec and specific components as required by Apple to meet full qualification. We use the same top grade, top tier Major Brand memory devices that are used for the memory modules Apple factory installs. We offer Netlist because of the relationship with them, to give our customers a choice where there may be a long standing loyalty to the Netlist brand, and also to be able to offer product that had Apple certification for those in positions where a requisition may require such extra rubber stamp.
DIGLLOYD: What about dual-rank vs single-rank vs quad-rank modules eg performance?
All current 1GB Mac Pro FB-DIMMs are by definition Single Rank.
All OWC 2GB and 4GB FB-DIMM modules are Double Rank. As you noted in your article, there is a performance advantage with the bandwidth on double rank vs. single rank.
There also exist Quad-Rank 4GB modules out there (and maybe 2GB as well) - but Apple specifically restricts their support in the EFI Firmware (even though they can work with the Intel platform in the Mac Pro). Counter to what you’d expect, and likely one of the reasons Apple doesn’t allow their use, Quad-Rank modules had substantially SLOWER data throughput vs. both single and double rank.
We have 800MHz Mac Pro memory throughput testing using the STREAM test with configs of 1GB, 2GB and mixed- online here.
DIGLLOYD: I haven’t verified the figures cited above by OWC, but the figures are consistent with my test results. Bottom line for 8-core Mac Pros, using 4 or 8 matched FB-DIMMS makes a BIG difference in performance. Don’t cripple your machine by using only 2 modules, or mismatched modules.
However, if you install 4X2GB modules and an extra pair of any other size (6 modules total), that extra RAM is likely to be scarfed up by caching, and system performance could actually improve overall; it will depend greatly on what you are actually doing, where programs load, etc. It’s hard to imagine (for example) that 10GB as 4X2GB + 2X1GB won’t work better under duress than 8GB alone.
In terms of faster data throughput, with the current 800MHZ machines – the difference is there with all the Quad-Core x 2 (8-Core) systems, while with the 2.8GHZ Quad x 1 low end unit, no matter how much memory or what rank – even with the two stock modules you’re basically at the max memory throughput... That however, does not diminish the ROI for having more memory installed. Different things going on and more memory makes a difference with even older, single processor systems and of course all the way forward and up from there. :)
DIGLLOYD: How much memory has OWC shipped?
We’ve shipped literally hundreds of thousands Gigs of our OWC Mac Pro FB-DIMMs and they are truly 2nd to none. Thanks!