Intel's Core 2 Extreme QX6700: The Multi-core Era Begins
by Anand Lal Shimpi on November 2, 2006 2:14 AM EST- Posted in
- CPUs
Using a Quad Core System
Intel's first dual core processors, codenamed Smithfield, were actually the first 90nm Intel CPUs we actually recommended. The reason being that the real world performance improvement brought about by having two cores at your fingertips was simply too much to resist, especially if you were a heavy multitasker. A big reason for the improvement in real world performance came about because of inefficiencies in the way Windows XP's scheduler handled juggling multiple threads, especially on a single core CPU. The move to dual core got rid of many of those nasty Not Responding windows when Windows' scheduler would simply never properly allocate CPU cycles to a particular thread.
Inevitably the same thread juggling problems we saw with single core CPUs would eventually apply to dual core CPUs, just with more active threads. Intel once told us that we'd run into the same sort of scheduler/CPU cycle limitations at a bit over a dozen active threads on a dual core CPU, meaning at that point, it's time for four cores.
We performed a quick test to see if we could spot the real world difference in multitasking and system responsiveness between a dual core and a quad core CPU. We took our test bed and ran as many multithreaded benchmarks as we could feasibly start without completely bogging down the system; we ran our 3dsmax, Cinebench, DivX, WME and iTunes tests all at the same time, not to see how fast they'd run, but to see how responsive the rest of the system would be with a dual core CPU vs. a quad core CPU.
On both systems we had no problems launching Explorer windows or navigating the OS while all of those tasks executed, indicating that we were no where near that saturation point where the entire system becomes unresponsive; good news for dual core owners.
We could switch between all of the running applications without running into a window that wouldn't respond, with the exception of iTunes. Regardless of whether we had two or four cores at our disposal, iTunes would only respond when it felt like it. Although the encoding task was continuing, we couldn't interact with the application without waiting a handful of seconds for it to regain consciousness.
The primary difference between two and four cores in our very heavy multitasking scenario was in the work that got done. While the 3dsmax, DivX, WME and iTunes tests all managed to inch along during our test, with a dual core setup the Cinebench test wouldn't even start until after iTunes had completed. On the quad core setup, Cinebench ran alongside iTunes, albeit at a slow pace.
It's a faint difference but it does highlight an important point - even the heaviest of multitaskers aren't likely to see a huge difference in system responsiveness with four cores vs. two. It is in the performance of individual threads, especially when you have a lot that are contending for CPU time, that you'll see a much bigger difference between Kentsfield and Conroe.
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JarredWalton - Thursday, November 2, 2006 - link
I am quite sure that 4x4 is for 1207 and not AM2. Sorry. I am also quite sure that 1207 will get quad core support, so long-term a 4x4 (dual dual core) can become... 4x8? (dual quad core). Anyway, in that sense it's just like Core 2 Duo and Quad.The questions I don't have answers to: will the 4x4 begin with a K8L chip, or just a tweaked K8? Will K8L be more competitive with Core 2? When will it finally come out? How much will it cost? Actually, I can sort of guess on the last point that 4x4 will cost a lot more than a Core 2 Quad config as you will need a more expensive mobo, RAM, and two CPU packages.
I *think* Anand plans to have an article delving into 4x4 and AMD's plans more in the future. Maybe he's still gathering data from AMD? (Sort of like squeezing water from a dry spongue at times, unfortunately....)
johnsonx - Thursday, November 2, 2006 - link
I don't think you're right on that one; 4x4 CPU's will use the same RAM as AM2 CPU's do. The "more expensive RAM" requirement is only for Opterons, which of course use registered ECC memory. In fact, if your chosen mainboard has memory banks for both CPU's, then you could even save a little since 4 smaller DIMMs tends to cost a little less right now than 2 bigger DIMMs.
JarredWalton - Thursday, November 2, 2006 - link
Except that like socket 940 vs. 939, I expect all 1207 boards to require registered DIMMs. I don't know of any dual socket board that doesn't.Griswold - Thursday, November 2, 2006 - link
The whole "catch" of 4x4 was that there are no ECC/Registered DIMMS required - at least that was the synopsis all the time. It should have very little to do with the socket itself, rather a matter of IMC, no?Anand Lal Shimpi - Thursday, November 2, 2006 - link
You're correct, 4x4 will use Socket-1207 CPUs but without Registered memory.Take care,
Anand
JarredWalton - Thursday, November 2, 2006 - link
I stand corrected, though I have to say I'm still not at all interested in getting a dual socket motherboard. LOL I guess 1207 CPUs will have to support both registered and unbuffered DIMMs? I can't imagine AMD trying to get people to make sure they get the right type of CPU for the RAM they're using.Second thought: could they have mobos and CPUs that will support both registered and unbuffered DIMMs? I think they have the same keying, so it's possible, right?
smilingcrow - Thursday, November 2, 2006 - link
Two dual-core 90nm 120W CPUs = No thank you.Two quad-core 65nm xW CPUs = interesting!
Jedi2155 - Thursday, November 2, 2006 - link
I'm personally a extremely heavy multi-tasker and I can't wait for quad to a hit a more managable price range. At the moment, they're just beyond my reach for a CPU alone. Once it hits around 300-500 then I would definitely buy one, but these right now are still for the rich and video encoders.AlabamaMan - Thursday, November 2, 2006 - link
I am still amazed by the fact that a $300 E6600 consistantly beats the $700 FX62Aikouka - Thursday, November 2, 2006 - link
That fact, my friend, is why I'm purchasing an E6600 in this upcoming week :). Simply the best performance without overclocking for the buck.