mac pro 2009 ram speed

in Genius Bar edited January 2014
I have been waiting since the mac pro 2009 came out in order to officially find out if you can install 1333 ram in stead of 1066 and if system profiler will actually indicate 1333.

I have not seen anything online yet about people trying out these tests. Or at least confirming if it is possible. I want to make sure before I decide to purchase my ram upgrade.

ANy ideas? Will installing 1333 ram eventually benefit me if I have the dual 2.93? Is there any chance that something will be done in order to utilize the 1333 ram if I have it installed?


  • Reply 1 of 2
    kmac1036kmac1036 Posts: 281member
    no, I wouldn't take any chances on that RAM working. Buy the RAM it's asking for.

    the 1333 has a bigger cas latency = 9 vs. the 1066 at 7. lower cas time is more of a speed booster overall than the clock speed.

    so, my feeble math is telling me, you would have 1.25x speed bump in clock, but also 1.28x increase in latency. In lay terms, the 2 would cancel each other, making the "upgrade" useless.

    anyone jump in & correct me if I'm worng on the numbers.

    also, the memory controller is intergrated with the processor on the new Xeons, so if any speed increase were to happen, it would either be a firmware update from intel (unlikely) or a processor swap for one that does support the extra speed.
  • Reply 2 of 2
    mfagomfago Posts: 24member
    I am curious too -- you see, the processor that Apple is using has finally been released 'officially' by Intel (a week or two ago), and Intel claims that the integrated memory controller in the higher-end CPUs (the 2.9 GHz for instance) is capable of DDR 1333. Perhaps Apple simply lists 1066 as that is the lowest-common denominator of the CPUs that they sell, but the high-end processor should support 1333. However, until someone actually tries this, no one can be sure that Apple didn't somehow limit their motherboard to 1066.

    Ad for the CAS latency of 1066 vs 1333, I'm pretty sure that depends on the RAM in question. Don't forget that the CAS latency is in terms of the clock-speed. So even if the two latencies were equivalent in terms of nanoseconds, the bandwidth of the 1333 would be higher.

    Another related question: when is Apple going to offer the 3.2 GHz CPU?

    Finally: those who think Apple's new Mac Pro prices are way too high should check out prices from Dell and HP. I priced out a 8x 2.93 GHz with 12 GB of memory, and Apple was _WAY_ cheaper than Dell or HP. The only issue is the lack of Quadro cards on the Mac. I'd have to blame Intel for the really high prices of the Nehalem Xeon CPUs themselves.
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