Intel's Core 2 Extreme & Core 2 Duo: The Empire Strikes Back
by Anand Lal Shimpi on July 14, 2006 12:00 AM EST- Posted in
- CPUs
Memory Latency: No Integrated Memory Controller Necessary
One thing we pointed out in our earlier preview coverage of Intel's Core 2 Extreme is that the new processors have extremely low latency memory access, despite relying on the same memory controller as the previous generation of Intel CPUs.
Without an on-die memory controller Intel's Core 2 processor must use the memory controller in its chipset, which currently means the 128-bit DDR2 memory controller in either Intel's 965 or 975X chipset. The confusing thing is that although the Core 2 processors use the same memory controller as the old NetBurst processors, memory latency has been improved tremendously:
Intel's Core 2 processors now offer even quicker memory access than AMD's Athlon 64 X2, without resorting to an on-die memory controller. While Intel will eventually add one, the fact of the matter is that it's simply not necessary for competitive memory performance today thanks to Intel's revamped architecture. Update:As many astute readers have pointed out, Core 2's prefetchers are able to work their magic with ScienceMark 2.0, which results in the significant memory latency advantage over AMD's Athlon 64 FX-62. This advantage will not always exist; where it doesn't, AMD will continue to have lower latency memory access and where it does, Intel can gain performance advantages similar to what ScienceMark 2.0 shows.
| CPU | Everest |
CPU-Z 1.35 (8192KB, 128-byte stride) | CPU-Z 1.35 (8192KB, 64-byte stride) |
| AMD Athlon 64 FX-62 (2.8GHz) | 45.9 ns | 43.2 ns | 19.3 ns |
| Intel Core 2 Extreme X6800 (2.93GHz) | 59.8 ns | 52.8 ns | 10.9 ns |
Because of the Core 2's intelligent prefetchers doing too good of a job with ScienceMark memory latency test, we wanted to also showcase situations where Core 2 would feature slower memory accesses than the AMD platform with its integrated memory controller. Everest's results are more in line with what we'd expect to see, with the FX-62 offering over 23% faster memory accesses than the X6800. CPU-Z's latency tool also reported somewhat similar findings, with an 18% performance advantage due to AMD's integrated memory controller. CPU-Z also provided us with numbers that showcase how well Core 2 can perform if its prefetchers are able to "guess" correctly; at lower strides the Core 2 Extreme manages faster memory access than the FX-62. The 128-byte stride numbers are indicative of what will happen if the pre-fetchers are not able to get the Core 2 the data it needs, when it needs it, while the 64-byte numbers show you what can happen when things go well.
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bob661 - Friday, July 14, 2006 - link
I would like to know about the AMD EE CPU's myself. I forgot about those.bob661 - Friday, July 14, 2006 - link
LOL! I got modded down because some of you clowns don't like to be accused of being hypocrites. So I'll ask a question. What's the difference between launching a video card and not having product available and launching a CPU and not having product available? I hear NO bitching at all on this. Why is that?epsilonparadox - Friday, July 14, 2006 - link
I don't get where you're seeing its not available. According to a poster above,How are we being hypocrites?
bob661 - Friday, July 14, 2006 - link
Beacuse this is a paper launch and no one's complaining but when ATI/Nvidia does the same thing everyone and their mom's are bitching and complaining. Hypocracy!Shintai - Saturday, July 15, 2006 - link
How can be it a paper launch when Intel first launches it July 27th?After July 27th you can start whine...
epsilonparadox - Friday, July 14, 2006 - link
How could it be considered a paper launch if there are posters above you complaining the their OC results of the C2Ds that they bought and have in their possession aren't as good as AT's?bob661 - Friday, July 14, 2006 - link
One poster gave a link to Newegg but there's nothing there. I searched the site and saw nothing. I also checked ZZF and Monarch. Nothing there. If this CPU is available, why can't I buy it?epsilonparadox - Friday, July 14, 2006 - link
As you said yourself before, the supply is tight hence the ridiculous price. If they've been available then they were already bought. http://www.buy.com/prod/CORE_2_DUO_E6600_DC_LGA775...">Check buy.comIts temporarily sold out but the orders placed when it was in stock were shipping july 5th.
bob661 - Friday, July 14, 2006 - link
That's a little high but not out of line. I paid $400 for my 3500 and this is MUCH faster. I am surprised that no one here has one of these since they were released earlier.Questar - Friday, July 14, 2006 - link
Because people were able to buy these four days ago?Because the official launch is still two weeks away?