Intel Core i5, Core i7 800 Processors and P55 Express - HotHardware

Intel Core i5, Core i7 800 Processors and P55 Express

1 thumbs up

One of the major changes brought forth with Intel's new Core i5 and i7 800 series processors is their packaging. These new processors are configured with 1156 contact pads on their underside, as opposed to the 1366 pads used on the original Core i7 processors.

  
Intel Core i5 750 Processor, LGA1156 Packaging

The changes made to the Core i5 and i7 800 series processors' packaging were necessitated by the integration of PCI Express connectivity, the dual-channel memory controller configuration, and enhancements / changes made to the chip's power delivery configuration. Due to the fact that these new processors use different packaging, a new socket is also necessary of course. More on that a little later.

The Core i5 chip pictured above looks nearly identical to a Core i7 800 series chip. In fact, the two processor lines differ only in their support for HyperThreading--the Core i7 800 series supports HT, the Core i5 does not. The processors are outfitted with integrated heat spreaders and have a number of surface mounted components on their undersides. There are also a number of contact pads on the top side of the chips.


Lynnfield Die Map

Underneath the heat spreader lies a native, quad-core CPU design, manufactured using Intel's 45nm process. The image above is a map of a Lynnfield die; it details the positions of each of the processor's major functional blocks. As you can see, the quad-execution cores are situated about in the center of the die, sandwiched between the new dual-channel DDR3 memory controller and 8MB of shared L3 cache. Miscellaneous I/O resides on the left and 16 lanes of PCI Express 2.0 are on the right. The integration of the memory controller and PCI Express lanes on the chip, essentially eliminated the need for a northbridge, like previous Intel chipsets. Hence, the single-chip P55 Express was born.

As we've already mentioned, Lynnfield is based on the Nehalem microarchitecture. But the changes introduced with Lynnfield make it quite different from the first batch of Core i7s. The changes made with Lynnfield culminate in a product that Intel claims is 20% faster than the previous generation Core 2 processor series, while also offering ~50% lower idle power consumption, and because the accompanying P55 Express chipset is a single chip design, there is a 40% total package size reduction (CPU + Chipset).


Core i5 and i7 800 Series Turbo Mode Illustration

Aside from the integration of on-die PCI Express connectivity, perhaps the most significant change made with Lynnfield in is regard to its Intel Turbo Mode functionality. With the original Core i7s, Turbo Mode allowed the chips to operate at one or two speed-bins above their "stock" frequencies, thermal and power envelopes permitting. With the new Lynnfield-based Core i5 and Core i7 800 series processors, however, Turbo Mode is much more flexible, and powerful.

With Lynnfield-based processors, Turbo Mode allows the chips to operate at up to 5 speed bins above stock. As long as the processors are running within specified thermal and power limits, when a single-threaded workload is detected, the clock speed on a single execution core will be increased up to 5 speed bins. When a lightly threaded workload is detected, frequencies will be increased up to 4 speed bins. And with a highly threaded workload, frequencies will increase 1-2 speed bins. As a result, the Core i7 870 will hit speeds up to 3.6GHz, the i7 860 up to 3.46GHz, and Core i5 750 up to 3.2GHz.
 

Article Index:

0
+ -

AMD is gonna be in trouble again.  Many people rightfully opted for a Phenom II 955 instead of an i7 920 because the performance wasn't much slower, but it cost much cheaper.  With the i5 750 priced similar to the 955 (and cheaper than the 965) once again AMD's entire lineup is gettled shuffled into the sub $200 market.  AMD still wins at a number of price points below that price, but it's a shame that AMD can't come out with something a little faster.  Still, good for the consumers who now have a really good CPU at around $200.  At least you can still go DDR2 (which is still cheaper) with the Phenom II line so you can still always build a cheaper system AMD style, but $200+ is now exclusively Intel.

Gaming is mostly my interest, so I'd like to see some high settings and resolutions benchmarks comparing the Phenom II 955 or 965 and the i5 750.  Low settings makes sure it is not GPU dependent, but I want to see GPU dependence too.  If say the 750 gets 33.8 and the 965 gets 32.2 (made up numbers) in Crysis at 1920x1200, then we can still say that AMD is "good enough" and can be noticably cheaper with the DDR2 route.  However, if the i5 still has a decisive advantage at the highest settings, showing that it can make a GPU really shine to its fullest, then we can say AMD is really toast at a price point above $170.

0
+ -

News:
At $199, the Core i5 750 can easily be considered a hot new mainstream quad-core offering.

Except for the fact that, as I write this, NewEgg and TigerDirect are charging $209.


0
+ -

Super Dave:

News:
At $199, the Core i5 750 can easily be considered a hot new mainstream quad-core offering.

Except for the fact that, as I write this, NewEgg and TigerDirect are charging $209.


NEWSFLASH: The price has dropped to $206.99!

 

0
+ -

Yeah, pricing is weird. Amazon has the i7 860 for $356. Expect that to come down REAL quick, since Newegg has it for $300. That's better, but wasn't the MSRP on that one $285?

At this point I'm going to put my new system build on the back burner. It appears, though, that I can get better value out of an 860-based system than a 920; unless someone can prove that triple channel memory does way better than dual channel. As far as I can tell, that and the integrated Northbridge are the biggest differences.

0
+ -

Well if you want to OC it there are some differences.  The integrated PCIe controller has it's power tied to the Uncore.  So you won't be getting those crazy 4Ghz OCs on stock voltages.  You have to crank up the juice.

The dual channel memory controller with DDR3 1333Mhz can fully handle three of the cores hitting at max output.  Only place you'll take a hit there is with high demand apps that use all your cores or in things that are extremely memory intensive. 

As a side note, all the comparisons of memory bandwidth and such between them that I have seen (except here) have had the 900 series using DDR3 1066Mhz memory.  But even using slower memory the tri channel (of course) has higher bandwidth.  And that gap just expands with higher speed memory.  However, only when running more than 1.5 cores per memory channel flat out or in extremely memory speed limited situations will you see an advantage from the tri-channel.  I have 12GiB in my system and normally see 8~10GiB of it used, but then I try to keep as much stuff in memory as possible (plus added the pair of SSD's in RAID0 for the stuff that couldn't be there).  Memory resident with high bandwidth (specially backed by SSDs) makes the whole system feel silky smooth.

0
+ -

How does the turbo thing affect overclocking? I would think that would make for a bit more work. Having to test each core to see if each one can run at the high speed when they are the only one maxed out.

0
+ -

Well, their turbo in the new chips goes up to 5 speed bins higher, compared to only 2 on the 900 series.  If your upping the juice and want to keep turbo mode on, then it is best to clock the 700 and 800 series to something that will net you 3.8~4Ghz with a 5 speed bin increase.  If you turn the turbo mode off (add up the volts), it looks like most sites are hitting 4~4.2Ghz.  Oh, both of the above are with a non-stock cooler.  Seems the stock cooler is not very good at OCing.

If you don't up the voltage, the highest I have seen was about 3.46Ghz.  That PCIe on die gets unstable and messes things up without the extra voltage.

As for the question about cooling it, any decent after market air cooler will work.  The stock cooler is not up to OCing with extra voltage though.

 

Cheers

0
+ -

>The stock cooler is not up to OCing with extra voltage though.

Is it ever? ,)

 

Being a belt-and-suspenders sort, I'd go with overcooling rather than undercooling, even if I wasn't reaching for the skies as far as overclocking. $65 for a Thor's Hammer or Megahalems (not counting fans) is a small price to pay, and the new lines of water coolers look promising and competitive.

 

Still, I'd like to see a review site do some testing on the temperature range we can expect from the new chips.

0
+ -

@InfinityzeN: That sounds well-ordered. What you said appears to support buying an 860 if your needs aren't too extreme-- and since I'm designing the new system to be a decent World of Warcraft rig at 1680x1050 resolution, "not too extreme" describes it well. Bob_on_the_cob also convinced me that I don't need a CrossfireX setup, though I'd buy a motherboard that has that capability, in case someday there's an advantage to running more than one graphics card for WoW.

 

I also wonder about the heat produced by the Lynnfield chips. I'm not a crazymad overclocker, but I'd try to get a little extra juice out of the processor. I'll be looking forward to reading about temperature testing of the new chips to see whether liquid cooling or a massive air cooler is required, or whether I can get away with a quieter solution.

 

But I'm definitely waiting for prices to stabilize.

Login or Register to Comment
Post a Comment
Username:   Password: