jay2tall :
... A BIG reason is the new x58 chipset. It also uses QPI (QuickPath Interconnect) rather than the FSB to communicate with memory.
Yes, but... Well, there is only one consumer chipset for the i7 currently and, my undestanding is, that chipsets for the i7 have to work that way. so whether you describe that as '...because of the chipset...' or '...because of the i7...' is, at best, a semantic distinction.
And, its also, effectively, the way that hypertransport works on AMD processors.
This is an advantage because core-to-core communication can occur without blocking core-to-memory-controller communication.
Hyperthreading is the main reason. The I7 is a part time 8 core processor
I'm going to disagree that its the
main reason; in some applications, hyperthreading is a real advantage, but in some it slows things down. Partly, you have to ask yourself, for how many applications today, is 4 (single threaded) cores not enough?
In future, as more and more apps can take advantage of thoroughly multi-threaded processors (more than just one thread, times the number of cores), this will increasingly become an advantage, but today its probably close to being a wash, depending on which apps you mostly run.
I think the improvements in the micro-architecture the cache and the on-chip memory controller are probably the biggest contributors in cases in which extra virtual cores isn't helping. but, in reality, there are probably several features each of which makes quite a moderate contribution on their own, but together it all adds up.
and other quad cores do seem to perform better than the i7, like a Q9550
One of those is a processor, the other is a family. If i choose the fastest member of the i7 family, no other consumer processor will get close in most benchmarks. But I'll be broke and won't be able to afford the electricity, which isn't ideal...
I wonder why Core 2 didn't have HT, they had the technology.
Because it didn't have to, and it would have been a lot of work. The p4 was a long decode queue, high clock speed processor, with a (relatively) low Instruction per Clock count. With a long pipeline part every pipeline stall causes a long wait while the pipeline refills and this causes a loss of performance.. as the clock goes up and up in pursuit of decent performance, the pipeline stalls eat a higher and higher proportion of the apparent perf gain from the clock speed. You can, however, minimise the performance loss by having more pipelines and refilling one in 'spare time' so that when the first pipeline stalls, you swap to the second and you no longer have to wait the full time for a pipeline refill.
So, the advantage of hyperthreading is a function of how badly stalls were going to eat into your potential performance.
When the core 2 parts came out, the clock speeds were relatively low (with the improved ICC, roughly half the clock speed of a P4 got you comparable performance, although part of that is also a function of cache size and arch, so you can't just say its a core function; its really the system working together).
So, the original core 2 parts would not have benefited from hyperthreading, or at least not to anything like the same extent as the P4 parts did, but as clock speeds rise the problem starts to press in on these parts, too.
I'm sure their R&D threw that idea around.
For sure. They would have had to do a complete new detail design of the system to make it work with the core 2's revised pipeline and they were (sounds difficult to believe now) under the cosh from AMD and were desperate to get the core 2 parts out as quickly as possible. How things change!
I thought the i5 was going to be quad core, but will only support dual channel DDR3. From what I read as well it won't be binned as high as the i7 so OCing won't be as crazy as the i7.
Doesn't that mean overclocking might be even crazier? For marketing reasons, the i7 will probably always have the highest specified clock frequencies, but the fundamental processes geometries will be the same. That means that the i5, in reaching the same absolute clock frequency, will have overclocked higher in terms of the ratio. Might need some pretty special memory to do it, though, as I'm guessing there probably won't be an unlocked/extreme edition i5.
^ no, i5 is the mainstream sector I suppose you could call it.
i5 includes dual cores, quad cores, then after a while hexa cores and octa cores.
4 HT's, so basically a slightly more powerful intel atom dual core?
You are right that i5 is aimed at mainstream, which the i7 wasn't. The only question is, how fast intel want to finish off the s775 platform in the mainstream and get the transition to happen. Maybe they'll be happy running out new Celerons and Pentiums on s775 for a while, but my guess is that s775 won't get much other development once i5 is available and they may even want to kill off the mainstream core 2 duo and quad parts quickly, too.
i5 will be way more powerful than an Atom. The Atom's ICC is notably low and the clock speeds aren't pushing the limits either, so its not a speed demon. the i5 won't be all that far off the i7 at the same clock speed and assuming that they allow it enough cache. From a marketing point of view, it rather depends on whether they are more interested in making a clear gap between i5 and i7, or hitting back at AMD in the mid-market. If they want a gap, they reduce the cache to about half of the i7, or even less, and sell the platform at prices that really hits AMD. Otherwise, it gets more cache, the prices are a bit closer to the i7, but the performance is too, but the faster Phenom II, still AMD's top and therefore most profitable, parts are in trouble. (And the remaining core 2 range turns into celeron's and pentiums and they take on the AMD parts below the Phenom IIs).
tri channel memory (the only one of its kind at least for right now)
Probably technically true, but don't some of the (serverworks?) server chipsets have four channels? Yeah, I know that's not three, but if three is better than two, doesn't four trump three? And, I guess if you've got four channels, you could decide to only use three of them. Probably.
but what is hyperthreading? also, ive seen some benchmarks and other quad cores do seem to perform better than the i7, like a Q9550
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