David Murphy, PC World
Sep 8, 2009 12:01 pm
Intel's two new Core i7 CPUs (860 and 870) are mid-range counterparts to its top-of-the-line Core i7 900-series chips, and initial tests (using Intel's new DP55KG motherboard) indicate their performance follows suit. Our early tests also show the new entry-level Core i5 750 is the one to watch when it comes to best bang for your buck. Intel's full processor breakdown--including the axing of its Core i7 940 processor--includes some potentially confusing differences between the chips. So here's what you need to know.
The existing Core i7 900-series processor lineup, codenamed Bloomfield, now features three separate products: 3.33-GHz Core i7 975, 3.06-GHz Core i7 950, and 2.66-GHz Core i7-920 processors. Between the Core i7-950 and Core i7-920 processors sit the new "Lynnfield" 2.93-GHz Core i7 870 and 2.8-GHz Core i7 860 processors. The brand-new, 2.66-GHz Core i5 750 CPU is a Lynnfield chip as well, but we'll get to that odd duckling further below.
Technology Differences
Intel took a big leap forward in the design department when it launched Core i7 900-series processors last November. Just a few of these included a new triple-channel memory controller integrated into the chip, a new QuickPath Interconnect system to replace (and improve upon) the front-side bus architecture of old, and the return of hyperthreading that split the chip's four physical cores into eight virtual cores for increased system performance. As the Core i7 900-series chips were based on a new Intel X58 chipset and LGA1366 socket, aspiring upgraders had to invest in new motherboards to reap the benefits of the Core i7 900-series platform.
That part still rings true for the new Core i7 800-series and Core i5 CPUs--all three run on Intel's latest P55 chipset and LGA1156 socket, which necessitates a new motherboard purchase for use. What's changed, however, is that the Core i7 800-series and Core i5 CPUs each adopt different permutations of the fanciest of the Core i7 900-series' features.
All three chips have dropped down from a QuickPath Interconnect and triple-channel memory controller to a Direct Media Interface and dual-channel memory controller. But don't freak out; This is more a loss of future-proofing than anything else given the minute performance differences between current dual- and triple-channel memory configurations.
An integrated PCI Express graphics controller on the Lynnfield CPUs can either deliver 16 lanes of bandwidth to a single PCI Express 2.0 videocard or split this connection into two x8 lanes for an SLI or CrossFire setup. Although it's a cut from the full 32 lanes (for a dual 16x or quad-8x configuration) provided by Core i7's X58 chipset, the bandwidth reduction should only affect those crazy enough to SLI or CrossFire dual-GPU videocards on a Lynnfield setup.
Turbo Boost: Automatic Overclocking
The new Core i7 800-series CPUs and the Core i5 750 still support the same automatic overclocking functionality, or Turbo Boost, as the Core i7 900-series processors. However, this feature has been jacked up on the newer chips. Core i7 900-series CPUs will only increase their multipliers to a maximum of two additional steps according to system demands (effectively taking a 3.33-GHz processor to 3.6-GHz depending on how many cores are in use). The new Lynnfield processors are able to jump up five multiplier steps for the 800-series chips (taking a 2.93-GHz processor to 3.6-GHz) and four for the Core i5 750 (2.66-GHz to a maximum 3.2-GHz).
Performance
Both Core i7 800-series processors support hyperthreading the same as their Core i7 900-series brethren. The Core i5 750 does not-its four physical cores are all that will appear in your operating system's task manager. Even so, the CPU's noteworthy performance makes it an excellent value for its roughly $200 price. We only saw a performance difference of 5 percent between the Core i5 750 and the roughly $555 Core i7 870 (based on WorldBench 6 testing of the two CPUs on identical system builds). In fact, the Core i5 750's score of 127 falls right around the scores set by competing Value and Power PCs that use Core i7 920 processors.
Test Bed: Intel DP55KG Motherboard, 4GB DDR3 1333 RAM, ATI Radeon HD 4890 graphics, 2x Seagate ST3750630AS hard disks (Raid 0), Windows Vista Ultimate 64 bit Service Pack 2
So where does that leave the Core i7 870? Given that its price is almost identical to that of the high-end 3.06-GHz Core i7 950 CPU, a processor that natively runs faster than the 2.93-GHz Core i7 870, it's difficult to see the compelling reason to pick up this chip. The Turbo Boost feature of the Core i7 870 does ultimately beat the speeds of the Core i7-950's, but for the enthusiast market, the increased memory support and bandwidth for multi-GPU setups might not be worth giving up. The Core i7 860 is more reasonably priced at $285, provided you can make sufficient use of its hyperthreading functionality.
It remains to be seen just how far the Core i7 800-series CPUs will overclock compared to the Core i7 900-series chips-the lower power draws of the 800-series processors could make quite a difference in this area. As for the Core i5 750, this chip looks to be a solid winner for those looking to dip their toes into the Nehalem platform without breaking the bank-given Intel's dramatic price points, that's always a strong possibility.
"Intel's New Core i7 and Core i5 Processors Explained" Comments
Please ALSO speak in laymen's terms:
What is the difference between the Intel Core i5 and Core i7?
Sure, some engineering design differences so i5 is somewhat "slower" than i7 but performs well so i5 is a better value!
I guess this is what you really meant for those of us who do NOT care about the engineering specifics but the ACTUAL testing/performance of the chip!
Really, many of the PC World reviews could be written for those of us NOT in the engineering field!
Please ALSO speak in laymen's terms:
What is the difference between the Intel Core i5 and Core i7?
I guess this is what you really meant for those of us who do NOT care about the engineering specifics but the ACTUAL testing/performance of the chip!
Really, many of the PC World reviews could be written for those of us NOT in the engineering field!
--
Err...
quote]
Our early tests also show the new entry-level Core i5 750 is the one to watch when it comes to best bang for your buck...
We only saw a performance difference of 5 percent between the Core i5 750 and the roughly $555 Core i7 870 (based on WorldBench 6 testing of the two CPUs on identical system builds). In fact, the Core i7 750's score of 127 falls right around the scores set by competing Value and Power PCs that use Core i7 920 processors.
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It appears the biggest downside to both chips is the fact that both use 2 totally different sockets than the 2 common used right now. LGA775 and LGA1366 are teh 2 common sizes. Why couldn't Intel make either of these newbies use one of the 2? If the chips offer so significant difference from the 1366...why create a whole new socket? What a waste. So now they want motherboard manufacturers to basically make a backwards designed board for them? Sounds just like when Intel create Slot-1 which provided no benefit over socket 370 which they got sued for.
I personally only just moved over to LGA775 in 2006 when I moved to Vista, bec my already 10+ year old system was finally showing its age...which had dual slot-1 (server board)
I'll just use LGA 775 until Intel doesn't make CPU's for it anymore. My present board supports...all single, dual and quad cores based on this socket all the way up to just over 3Ghz...I am using the Q6600 so I have plenty of room to upgrade and the board supports ddr2/ddr3 ram...so I will get 10+ years out of it as long as the board holds up.
I will see what follows x58
Note to Intel...the i5 could have fitted into the 775 socket and given us and option to get some of i7 benefits without getting a new board, and teh new i7 could have just been made for 1366.
Hyperthreading is a gimmick.
i5 is to i7 as celeron is to pentium and the i5 will so not be worth it for most applications. I'll still buy an AMD over an Intel any day of the week. For that $200.00 that could spend on the i5 I can get an AMD Phenom II X4 940 Black Edition and get a lot more bang for the buck and have $10.00 left over for a little additional RAM.
ok guys - the i5 could not "fit" into the 775 socket - something about a wider bus, integrated memory controller, and 1156 pins. However, they are some seriously greedy bastards to remove triple channel support, and not use the 1366 that the (real) i7 sits on!
They did this specifically to kill any upgrade path a person might have.
EG: I go out, and buy an inexpensive i5 mobo, some ram, etc... and a year from now, when prices drop, decide to bump up to the i7... well now I get to buy another mobo, new ram again (to get the 3 matched pieces) etc. It is designed just to rip you off.
Then comes the big question, if you buy a gateway with an i7 - which i7 is it? the 1366 or the 1156? Don't even think gateway will make a point of telling you.
For the sake of mentioning it - this is also why I am sticking with AMD for new machines. I already built one on the Phenom X2 platform, at it is just amazing! Quad core, extreme OC ability, all the fixins for under $400! And AMD isn't playing the socket changing game!
@waldojim:
I couldn't agree more. Which is why I went with the AMD Phenom II X4 955 chip which, for $200, didn't break the bank and offers excellent performance. Intel is going in the wrong direction right now; they should be furthering the performance of their i7 processors and reducing the prices of existing ones, rather than making a WHOLE NEW SOCKET and lesser performance processors which just confuse the consumer and halt future upgrade plans.
AMD was king when Intel had the Pentium 4.
Intel was king when they had the Core2.
AMD is king again with their overhauled Phenom II design.
All Intel has done over the last 10 years or so is confuse consumers to the point where the processor version is completely meaningless to all but a select few with the time and inclination to sort it all out. Years ago people knew they wanted a 386, then a 486 then a P1, P2, P3, P4 after that, forget it. What a major marketing mistake. They let people walk right off the upgrade treadmill. I wonder what Marketing genius let that happen?
Several times you referred to the i7-750 processor, when in fact you meant the i5-750. I would greatly appreciate you being more careful in the future when it comes to referencing the processor model numbers. When someone is trying to learn the differences between the models and you keep confusing them, it really makes it much harder to learn or a more difficult read. Thanks for your time.
I copied and pasted the sections from the Porformance paragraphes to show what I'm referring too shown below in parenthesis.
(In fact, the Core i7 750's score of 127 falls right around the scores set by competing Value and Power PCs that use Core i7 920 processors.)
(As for the Core i7 750, this chip looks to be a solid winner for those looking to dip their toes into the Nehalem platform without breaking the bank-given Intel's dramatic price points, that's always a strong possibility.)
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