A 12MB L3 Cache: 50% Larger, 14% Higher Latency

Gulftown sticks to Ronak’s 2MB of L3 per core rule and has a full, 12MB shared L3 cache that’s accessible by any or all of the six cores. It’s actually because of the large unified L3 cache that performance in applications that don’t use all six cores can be higher than quad-core Core i7s.



The added cache does come at the expense of higher access latency. Nehalem and Lynnfield had a 42-cycle 8MB L3, Gulftown has a 48 cycle 12MB L3. A 14% higher latency for a 50% increase in size. Not an insignificant penalty, but a tradeoff that makes sense.

Identical Power Consumption to the Core i7 975

Raja has been busy with his DC clamp meter measuring actual power consumption of CPUs themselves rather than measuring power consumption at the wall. The results below compare the actual power draw of the 32nm Core i7 980X to the 45nm Core i7 975. These values are just the CPU itself, the rest of the system is completely removed from the equation:

CPU Intel Core i7 980X Intel Core i7 975
Idle 6.3W 6.3W
Load 136.8W 133.2W


Thanks to power gating, both of these chips idle at 6.3W. That's ridiculous for a 1.17B transistor chip. Under full load, the two are virtually identical - both drawing around 136W.

Westmere Goodness

The Core i7 980X is the first LGA-1366 processor based on Intel’s Westmere architecture, but unlike Clarkdale it does not have an on-die PCIe controller or on-package graphics. If anything, Gulftown really looks like a 6-core, 32nm version of Bloomfield rather than a scaled up Clarkdale. The similarities to Bloomfield extend all the way to the memory controller. Gulftown only officially supports three channels of DDR3-1066 memory, not 1333MHz like Lynnfield or Clarkdale. Of course running DDR3-1333 memory is possible, but the memory controller is technically operating out of spec at that frequency.

The processor does retain the Westmere specific features. The first Core i7 did not power gate its L3 cache, Lynnfield added it and Gulftown has it as well. While Mainly improved power efficiency and AES-NI instructions. I looked at the performance improvement offered by AES-NI acceleration in our Clarkdale review. If you use BitLocker or do a lot of archive encryption/decryption, you'll appreciate Gulftown's AES-NI.

Index The Roadmap: Sandy Bridge in 2011


View All Comments

  • Meghan54 - Thursday, March 11, 2010 - link

    [QUOTE]where are you getting your xeon pricing info from?

    all i can find from any solid source is the current xeon quad core processors which are running about $2000 on newegg at the moment. [/QUOTE]

    Well, I question your search skills at Newegg, then, if that's all you can find there.

    Just an FYI, Newegg has MANY, MANY sub-$700 Xeon processors for socket 1366, like the W3520, a Bloomfield, for $310, or the W3550 for $600--both Bloomfield quad-core cpus.

    Learn to use search, (ps....main page, cpu/processors, processors-servers, power search, check box socket 1366, look at results. I'm hoping you do understand that there are mouse clicks between step.)
  • formulav8 - Thursday, March 11, 2010 - link

    grow up... Reply
  • softdrinkviking - Thursday, March 11, 2010 - link

    no, i saw all of that stuff. i was looking at the six core chips and i typed quad instead.

    but thanks for getting all nasty and sarcastic anyway.
    i'll try to remember about those mouse clicks next time.

    the point i was trying to make is that the xeon line is going to be more expensive than the comparable home desktop CPUs and that it won't be a simple matter of non-server customers just buying xeons that will outclass the current i7 line-up. (specifically to compete against the 6 core model that this review is about)

  • Drag0nFire - Thursday, March 11, 2010 - link

    I think the point was that you could get 2x cheap quad core Xeons, and run with 8 cores (16 threads) at a small price premium over the $1000 Gulftown. Reply
  • vol7ron - Thursday, March 11, 2010 - link

    I will keep my eyes open for the Xeon, but for some reason, those typically are quite pricey. This $1k price will fall, hopefully sooner, rather than later.

    I am looking forward to both.

    Thanks for the read, Anand,
  • DrMrLordX - Friday, March 12, 2010 - link

    Here's a list of Gulftown quads for LGA1366:


    The information isn't complete, but you should be able to do searches on the part that interests you most and get the information that you want.
  • iamezza - Thursday, March 11, 2010 - link

    it won't be dropping in price any time soon. Check the chart on Pg 3 - this is the top intel CPU until 2011 and I can't see AMD releasing a CPU that will compete performance wise with it before then. Reply
  • DarkUltra - Monday, May 03, 2010 - link

    I also miss memory and cache performance tests, and memory overclock results. Reply
  • Kn0xx - Monday, May 17, 2010 - link

    well, this new 6 core comer, will be ( probably ) the entry design for 128 -bit processors that Intel are already working on it.

    128 bit need new multi-core structures. so ..980X is an example of how can a 128-bit core would be =)
  • unmaskedtruth - Sunday, May 23, 2010 - link

    does anyone know if protools le 8.0 is multi-threaded? for recording pro music, is it going to be able to take advantage of "6cores" if i was to go i7-980x route? or is quad-core more than sufficient? cause there is i7-930 which is cost like 80% less than the 980x. what do you guys suggest? Reply

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