Four Architectures, Four Chipsets, Tons Of Variables
Let’s break down our four hardware platforms for a better idea of what we’re about to see.
Core i5
First up is our Core i5 setup—arguably the most controversial configuration because it isn’t representative of any actual CPU model Intel is launching. The engineering sample we're using runs at 2.66 GHz by default and supports a single bin of Turbo Boost acceleration, locking it in at 2.8 GHz. Hyper-Threading is not supported, making this a quad-core processor able to execute four threads concurrently. In essence, it's a Core i5-750 without the ability to hit 3.2 GHz in single-threaded situations.
| Intel Core i5 @ 2.8 GHz | |
|---|---|
| Socket Interface | LGA 1156 |
| Chipset | Intel P55 |
| PCI Express Configuration | 1 x 16-lane, 2 x 8-lane |
| Core Configuration | Four physical cores, four threads (no HT) |
We ran our tests on an early version of Asus’ P7P55D Deluxe motherboard, which sports three PCI Express x16 slots, two of which are tied in to the Core i5’s on-die PCIe connectivity. With one graphics card installed, you get 16 lanes of second-gen PCI Express. With two, those lanes are divided into a pair of x8 links, thereby serving up to 8 GB/s per slot rather than 16.
Now, there should be some inherent performance advantages to putting connectivity on the processor die itself, rather than having graphics cards communicate through a northbridge and its interface to the CPU. Although GPU command streams are really the only data traveling over PCIe from GPU to CPU (and bandwidth consumption is purportedly negligible), texture data, video streams, and vertex data travel between system memory and the GPU. If i5 can do this faster than X58, P45, or 790GX, we might see a performance speed-up.
It'd be an easier comparison if we weren't swapping processor architectures every step of the way. We also have to consider that Core i5 gives up a single 64-bit DDR3 memory channel and Hyper-Threading, so LGA 1366 Core i7s could still technically be faster. The real question, though, is what happens when you adopt CrossFire or SLI, splitting PCIe between two high-end cards?
Core i7
This isn’t an issue with Core i7—at least the LGA 1366-based models (Intel is launching LGA 1156-based i7s, too). The X58 chipset includes enough PCI Express 2.0 connectivity to give each card in a two-way CrossFire/SLI setup its own x16 link. Moreover, with a QPI link running at up to 6.4 GT/s (moving up to 25.6 GB/s of data) between X58 and Core i7, there are no perceptible bottlenecks negatively affecting graphics performance.
If there is a reason to buy LGA 1366-based Core i7 platforms over LGA 1156-based Core i5s, this architectural detail will be it.
| Intel Core i7 @ 2.8 GHz | |
|---|---|
| Socket Interface | LGA 1366 |
| Chipset | Intel X58 |
| PCI Express Configuration | 1 x 16-lane, 2 x 16-lane, 1 x 16-lane/2 x 8-lane, 4 x 8-lane |
| Core Configuration | Four physical cores, eight threads (HT) |
We stuck to our reference platform for testing Core i7—Asus’ P6T motherboard. With one graphics card installed, it offers 16 lanes of PCIe 2.0. With two graphics cards installed, it serves up 16 lanes to both. The platform’s only real disadvantage is that Core i7 is officially rated to work with DDR3-1066 memory, while Core i5 ticks that up to DDR3-1333. It’s really a non-issue for most enthusiasts, though, since we’ve had our Core i7-975 Extreme running at up to DDR3-2133 speeds.
Finally, we did make one important concession in pitting Core i7 against Core i5. In order to match the clock frequency of the two platforms, we locked our i7-975 in at 2.8 GHz—similar to what you’d get from a stock i7-920 with Turbo Mode enabled. Again, we're analyzing PCIe performance here, and don't need processor clocks throwing off the results.
Well... the results from Crysis were very disappointing. It got outpreformed by an previous generation CPU, ah come on...
Nice review, interesting to see how the Phenom II is doing.
AMD doesn't have to improve, Intel is getting worse for them. ( in my opinion )
i keep seeing you reviewers bragging about core i7/i5 socket 1156 CPU's Turbo Mode giving it a major advantage or making it better than i7/X58 but how many people are actually going to run them at stock speeds? Once their overclocked Turbo Mode means nothing really, especially 1 and 2 core Turbo Mode. Also getting those 1 and 2 core multipliers is not easy, they dont always activate when games/apps are single/dual threaded because the other cores are still active and any background tasks or other executions will use the other free cores meaning that to consistently have the 1 and 2 core Turbo Mode multis you would actually have to disable the other 2 cores in the BIOS, which no one does even on the i7.
Did Intel throw all you guys a few sheckels to promote Lynnfield with this turbo Mode mantra?
^^ Oh for *GODS SAKE* would you effing fanboi muppets STFU? What is this 'thing' nowadays that when a group doesn't like news they just generate their own, join a group of likeminded muppets, make your delusion expand by shouting constantly at everyone then sit back condemning the purveyors of the truth as liars? I bet Obama's going to kill your grandparents with a deathpanel eh?
Let me answer your question with another question; what effing proportion of people overclock? One in twenty, if that? I'm certainly going to clock my 860 to 4.0-4.2, but what about everyone else, and how do overclocked Nehalem architectures compare to overclocked Phenom II's? they lose. Period. I've benched them myself you utter muppet. Right now AMD are using a moderate revision of the Athlon 64 architecture, if Bulldozer comes out swinging and wins, I'll be happy, until then, deal with it.
And stop mindlessly attacking journalists who don't conform to your fanboy view of the world. L2compute FFS.
whos the fanboy? sounds like the reviewer is and i am not sure what your problem is but i may seek counselling as your outrage and outburst over something thats pretty unimportant in the grand scheme of things is a little alarming.
Why would Obama kill my grandparents?
and if you dont overclock your i7 your basically giving up a free easy OC boost, atleast on the i7/X58, i have read that socket 1156 CPU's have a little trouble overclocking on stock voltage due to the PCI-E contoller and its voltage being tied in to other parts of the CPU.
I really dont get the core i5 platform. The processors are way too expensive and its a mainsream platform. Well, i think it pretty much fails as the price tag is high end.
whos the fanboy? sounds like the reviewer is and i am not sure what your problem is but i may seek counselling as your outrage and outburst over something thats pretty unimportant in the grand scheme of things is a little alarming.Why would Obama kill my grandparents?
You are the fanboy, not the reviewer. This is because the reviewer is telling it like it is, and you are being a complete idiot to try and discredit a perfectly sane point they made - all because you don't like the truth. That kind of thinking is destructive. Seek counselling for that and maybe your comments will have some value.
re Obama, L2readinternationalnews
Dont believe the hype, do, do, do, dont believe the hype.
This is the issue; it's not hype.
It's like Toyota bringing out a car with, oh, I dunno a battery that recharges when one brakes and your saying "uhhh don't believe the hype - the batter only works when you brake, what if you never brake???" The only conclusion I can come to is that you and your brethren are 'beyond extreme' AMD fanboys, or that this is some kind of pathetic attempt at 'buzz marketing' by AMD.
I'll leave it to everyone with two brain cells to rub together to work out which option is more likely and less pathetic.