Upgrading and Analyzing Apple's Nehalem Mac Pro
by Anand Lal Shimpi on July 13, 2009 5:00 PM EST- Posted in
- Mac
The Crossroads of Simplicity and Sophistication
Choices. Choices. Apple doesn’t like to present the end user with many choices. Too many choices can confuse, if left unchecked they can become overwhelming. The overburdening of choices is something that most PC OEMs fall victim to. I recently spoke with ASUS and brought this up in a conversation about the Eee PC. Three and four digit model numbers are how you tell one Eee PC apart from another. Perhaps you have the Eee PC 901, or the Eee PC 1000HA or the S101. To an enthusiast who has time to research these things, the model numbers aren’t that hard to figure out - it’s easier than Calculus after all. To someone just looking to buy “one of those Eee things”, it’s overwhelming.
Try buying an Apple notebook and you’re faced with two models: the MacBook and the MacBook Pro. If you’re a consumer, buy a MacBook, if you’re a professional buy the Pro version. Then just select your screen size and you’re done. That’s how Apple wants it to work and for the most part, it does. Very well.
Apple’s simple approach works quite well for consumers, but once you start getting into the high end content creation world it’s not quite so easy. How do you simplify the decision between two very fast cores and four slower cores or eight even slower ones? It wouldn’t really fit within Apple’s well kept home to ask its customers whether they run predominantly single threaded, lightly threaded or heavily threaded applications. Much to my surprise, the two new Mac Pros do effectively that. They present the end user with an option to choose four faster cores or eight slower ones. And there’s much more to the numbers that what Apple publishes on its own website.
These are the CPUs Apple offers on the new Mac Pro:
| Apple Mac Pro (2009) | Quad Core Model | Eight Core Model |
| Default CPU | 1 x Xeon W3520 (2.66GHz) | 2 x Xeon E5520 (2.26GHz) |
The clock speed difference appears to only be 17% at first glance, but there’s much more to the story.
Four or Eight Cores and the Magic of Nehalem
There are effectively three classes of applications that we have to consider when wondering whether or not the new Mac Pro is indeed a good buy. On one end of the spectrum we have single-threaded applications and tasks.
These days CPU performance improvements happen along three vectors: ILP, clock speed and TLP. The first vector of performance improvement is ILP (Instruction Level Parallelism). These improvements are changes to the micro-architecture. They could be as simple as adding a larger/faster cache, or as complex as a faster/more capable SSE unit. These days there are minor improvements in ILP between microprocessor generations. The second vector, clock speed, is also fairly stagnant. The Nehalem based Xeons run at about the same clock speed as the Woodcrest, Clovertown and Harpertown based Xeons that the older Mac Pros used. The final vector, TLP (Thread Level Parallelism), is where we’ve seen some of the biggest gains this round. As the name implies, execute more threads in parallel and you can get more performance. You increase the number of threads you can execute by running multiple threads on a core (SMT or Hyper Threading) or by adding more cores to a chip. Quad-core is still the sweet spot configuration for Xeons, but the Nehalem architecture brings Hyper Threading back to the limelight and now each of those four cores can work on two threads of instructions at the same time.
Well let’s look at how ILP, clock speed and TLP compare from Harpertown to Nehalem (for more details on what makes Nehalem tick, err tock, be sure to read our architectural analysis):
| Apple Mac Pro (2009) vs Apple Mac Pro (2006 - 2008) | Upgrade | Downgrade |
| Instruction Level Parallelism (ILP) | Faster memory access Minor microarchitectural updates | Smaller L2 caches |
| Clock Speed | Minor clock speed advantage in some cases | Minor clock speed disadvantage in others |
| Thread Level Parallelism (TLP) | Large L3 cache shared by all cores 2x threads per core (Hyper Threading) |
Looking at the table of improvements you should already know where to expect the Nehalem Mac Pro to excel. With each chip being able to execute twice as many threads as those used in the old Mac Pro, if you’re running a well threaded application then you’ll certainly see performance improvements on the new Mac Pro. What sorts of applications are “well threaded”? Generally things like 3D rendering and professional video encoding. The easiest way to find out is to fire up activity monitor and see how many of your cores are taxed while you’re using your system. If all of the bars are full of blue on a quad-core machine then you’d probably appreciate a Nehalem Mac Pro.
The clock speed improvements are minimal. In a non thermally constrained environment you can add 133MHz to whatever clock speed Apple puts on the box. So the 2.26GHz Mac Pro will most likely run at 2.40GHz and the 2.66GHz Mac Pro will spend most of its time at 2.80GHz, if you’re doing something CPU intensive that is. This is of course do to Intel’s Turbo mode.
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mfago - Monday, July 13, 2009 - link
Apple lists the Mac Pro as supporting DDR3 1066 only, yet the higher speed CPUs should support 1333. Have you tested this? I have an application that would love faster memory.Secondly, while Apple's prices are much higher than previous models (due to Intel's CPU prices, as you note), have you compared similar machines from Dell/HP? _Significantly_ more expensive: a T5500 with 2x2.93 GHz and 12 GB ram is $8000 (before discounts). Otherwise, the only way to get decent prices is through second/third tier vendors, or building one yourself. Sure CPU/RAM upgrades have always been this way, but Intel's extreme prices on Nehalem make this very obvious.
austin512 - Saturday, May 1, 2010 - link
Hi Anand,Any word on if the W3680 will work in the 2009 Mac Pro?
rominator - Thursday, July 22, 2010 - link
"While you could stick Clovertown into the first generation Mac Pros, you couldn’t upgrade them to Harpertown without hardware modifications to the system (don’t ask me what they are :)..)."AFAIK, nobody has ever discussed being able to do this. ANyone have an idea what he's referring to?
mrob27 - Thursday, September 23, 2010 - link
Upgrading CPUs:I have the 2.26 GHz 8-core model. I cannot afford to take the risk, but I'd love to upgrade it someday if it was less risky.
I think you should carefully measure the thickness of Xeon processors with and without the heat spreader (using an outside micrometer or something), and add washers to compensate for the needed spacing where the screws mate the heatsink to the processor board. This would properly relieve strain from the CPU package and allow you to tighten the hex nuts to the proper (standard) tension. Based on your photos it looks like that should work.
Turbo mode:
I was able to get valid convincing single-threaded benchmark results (demonstrating Turbo mode in action) by using the "Processor.prefPane" from Apple's Developer Tools. This is a System Preferences module that is placed in /Developer/Extras/PreferencePanes when you install the Dev Tools, and you copy it into /Library/PreferencePanes to enable it. Then use System Preferences to access it. You can turn off hyperthreading and can selectively disable any combination of cores 2-8 (#1 is always on). See for example goo.gl/7MZm or goo.gl/OH4K
- Robert Munafo - mrob.com/pub/comp/mac-models.html
Auralwiz - Friday, July 13, 2012 - link
Did you ever try the 2.26 8 core CPU upgrade?I tired two w35675s and failed to boot. Is there two big of a speed increase limit?
Michael
Highjnx - Sunday, November 7, 2010 - link
I recently tried to upgrade the E5520 procs in my 2009 Octo Nehalem with a set of X5560 (2.8GHz). I was able to get the machine to power up with no error lights. However I didn't get a chime and it refused to boot.In reading Anand's article on upgrading with a set of X5570 chips I didn't see any mention of the X5560 as an option. Is there something written into the bios that prevents this from posting.
The other thing I question is the added height created by the Integrated Heat Spreader doesn't give a solid connection between the daughter board and the heat sink fan plug. Has anyone run across a how-to on removing the IHS?
Any insight would be appreciated as I have access to several set's of X5560.
todd-
Auralwiz - Friday, July 13, 2012 - link
I purchased two w3565 LG 1366 processors for my 8 core dual 2.26 GHz 2009 Mac Pro 4,1.These CPUs are 3.2 Ghz.
The install was easy but the machine would not boot up. I re-installed the two 2.26 original CPUs and the system returned to normal. Any idea why it didn't work on an 8 core system?
I had the same experience as user Highjinx.
Michael
Soren4 - Sunday, June 12, 2016 - link
As a 2009 Mac Pro owner, I've followed the upgrade discussions for these machines carefully for some time. There appears to be a lot of discussion and instruction on how to swap out processors but usually involving lidded CPU's instead, which pose potential risks of damaging the motherboard in the process.I found an interesting video tutorial on Youtube today that clearly explains, while demonstrating, how to effectively remove the soldered IHS off the CPU, with the cleaning off of the solder, without damaging it.
It seems to me that this would be a lot easier to do than having to modify the heat sync pads and add washers etc., all the while allowing the processors to stay cooler due to the removal of the IHS.
Here is the link for review.
https://www.youtube.com/watch?v=aPhDfUkll-o
Thanks