Core i5 to Feature Lower QPI Multiplier

[btarunr]

Intel's newest line of CPUs, the Core i5 series is generating quite some buzz ahead of its release, with each piece of detail emerging about the processors adding to the attention it's gathering. Expreview has learned that the Core i5 series processors will feature a slightly different system interface in comparison to their Core i7 cousins.

Coming to the QPI interface between the CPU and NB dice, Intel will raise the QPI base frequency at the expense of lowering the multiplier. For example, the Core i7 uses a 20+ multiplier with a base frequency of 133 MHz. This frequency could be scaled up to 166 MHz at 24x multiplier due to the theoretical speed-limit of QPI at 8.00 GT/s. With the Core i5, Intel will set lower QPI multiplier values (around 16X), while upping the base frequency to around 250 MHz.



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[LittleLizard]

wait, i dont get a crap about this. the memory controller IS on the cpu but not on the same die of the cores? if is that, then it would have much lower performance compared to i7 because although the northbridge controller is still on the cpu, it still to travel out and in to comunicate to the nb die... WTF

 

[phanbuey]

erm... I need pictures.

 

[btarunr]

the memory controller IS on the cpu but not on the same die of the cores?

Yup.

Also:

There is a theory as to where exactly Intel will place the memory controller. I'm waiting for some confirmation. It says that on some models (that lack an IGP), the CPU die will hold a dual-DDR3 IMC (same basic design as the i7 die), while those chips with IGPs will have the CPU die without any IMC, the northbridge die will hold the memory controller and the IGP.

So far we know that Clarkdale (Core i5 dual-core) has a 32nm CPU die, and a 45nm NB die, while Lynnfield (Core i5 quad-core) has both CPU and NB dice built on the 45 nm process.

Need more sources on the IMC part.

 

[newtekie1]

I don't believe it has to send data out then back in again as long as Intel has an interconnected directly on the package for the two to communicate.

 

[razaron]

wait a minute, doesnt having a higher frequency mean its going to be faster than bloomsfield???? (minus the tripplechannel)

 

[Binge]

If I didn't know any better I'd say mulipliers aren't part of the total speed of any given chip

 

[OzzmanFloyd120]

Wow... I'm quite confused.
In dumbass terms, how fast is it in refrence to C2D/Q & i7

 

[MilkyWay]

this is confusing, if they run on the same board right and the northbridge has the memory controller on it does that mean that if the cpu has the memory controller and the northbridge there is going to be 2 memory controllers if you buy a cpu with one on it?

i mean for an i5 to work they need to have a northbridge with igp and memory controller off the cpu, but that means that having them on the cpu is pointless as then there would be 2

OH FUCK dont tell me they are going to bring out boards with no igp and memory controller on the northbridge and some with, that sucks meaning that if you choose to get a new cpu and yours has no memory controller onboard you need to get a cpu with one on it, cant choose the other type of cpu coz then there would be no memory controller

what is the point of this just make all cpus one way and all boards one way not have one with a controller one without

 

[newtekie1]

No i5 board will have a memory controller, and there will likely be none with IGPs either, unless nVidia decided to release one with an IGP on it.

 

[-1nf1n1ty-]

so....would an i5 be just as good as the i7's?(I know nothing about processors) if its almost as good I want one,lol

 

[eidairaman1]

Core i5 is more for the mainstream market, TBH i think it would of been wise to release lower model CPUs on the 1366 and skip the lower sockets, aka have the Mobile Market, Desktop Market and Server/workstation markets.

 

[farlex85]

Ah so here's the overclocking limitation. I was wondering where that would come in if it did. These still look close to i7, but they certainly won't clock as high.

 

[[I.R.A]_FBi]

what does that 250 mhz do for the performance?

 

[madrooster]

A 250MHz base frequency, will mean rather low multipliers compared to i7.

250MHz x 16 (as given in the article) is 4GHz.

Since the i5s are meant to be lower frequencies than i7 (there was mention of circa 2.5GHz or so) then the multiplier for a 2.5GHz would be 10x.

Lynnfield will have the IMC on the CPU die (there is only 1 die for Lynnfield).

Clarkdale will have the IMC on the IGP die and not on the CPU die. Nevertheless, this will not affect which motherboard you have to get. Clarkdale's IMC is rumoured to not be the same as Lynnfield's - it is apparently going to be based on the current G45's MC. Whereas the Lynnfield IMC will be based on the i7 one.

 

[FordGT90Concept]

what does that 250 mhz do for the performance?

The speed tells us that there is about half as many subsequent transistors as what is found on Core i7. They doubled the speed to make up for the transistors they removed. If this proves true, a Core i7 at 3.06 GHz (133 x 23) can process as much data as a Core i5 at 5.75 GHz (250 x 23).


The higher clockspeed and integrating the northbridge on the processor are both cost cutting strategies. We'll see how that translates to wholesale and platform prices though. Maybe, just maybe, the platform price will be down by about 20-30% because of these changes (instead of $200, it might cost $140, for example).

 

[Steevo]

Long story short, they DON'T want to sell a chip with enough FSB (or QPI) overclocking headroom to compete for cheaper than the more expensive chips, and they are releasing this PR bullshit to cover it up.

 

[btarunr]

this is confusing, if they run on the same board right and the northbridge has the memory controller on it does that mean that if the cpu has the memory controller and the northbridge there is going to be 2 memory controllers if you buy a cpu with one on it?

i mean for an i5 to work they need to have a northbridge with igp and memory controller off the cpu, but that means that having them on the cpu is pointless as then there would be 2

OH FUCK dont tell me they are going to bring out boards with no igp and memory controller on the northbridge and some with, that sucks meaning that if you choose to get a new cpu and yours has no memory controller onboard you need to get a cpu with one on it, cant choose the other type of cpu coz then there would be no memory controller

what is the point of this just make all cpus one way and all boards one way not have one with a controller one without

Capiche?

The most likely explanation for Clarkdale's design approach is because the IGP needs memory, and the best way to have some, is by having a memory controller next to you.

 

[OnBoard]

Long story short, they DON'T want to sell a chip with enough FSB (or QPI) overclocking headroom to compete for cheaper than the more expensive chips, and they are releasing this PR bullshit to cover it up.

But i7s struggle to get over 200MHz and i5 starts at 250MHz? Will they overclock at all or are they really so different that i5 can have so superior QPI link speed?

Somehow this all makes me think they are OC monsters and they need to have a low multi or no-one would get a i7. With 133MHx they do instant 4,5GHz upping the "FSB" to now stock 250MHz

Anyways they should get them out already and not just leak info every month to get free advertising. With all this "hype" they'll flop having nothing short of near i7 performance.

 

[FordGT90Concept]

But i7s struggle to get over 200MHz and i5 starts at 250MHz? Will they overclock at all or are they really so different that i5 can have so superior QPI link speed?

Somehow this all makes me think they are OC monsters and they need to have a low multi or no-one would get a i7. With 133MHx they do instant 4,5GHz upping the "FSB" to now stock 250MHz

Anyways they should get them out already and not just leak info every month to get free advertising. With all this "hype" they'll flop having nothing short of near i7 performance.

See what I said above. The Core i7 can probably do a lot more per clock than the Core i5; hence, not needing as many clocks. If all you care about is clockspeeds, yeah, the Core i5 is going to be better for you than the Core i7; however, if you care about throughput/processing power, Core i7 still has a strong upperhand.

 

[Steevo]

But i7s struggle to get over 200MHz and i5 starts at 250MHz? Will they overclock at all or are they really so different that i5 can have so superior QPI link speed?

Somehow this all makes me think they are OC monsters and they need to have a low multi or no-one would get a i7. With 133MHx they do instant 4,5GHz upping the "FSB" to now stock 250MHz

Anyways they should get them out already and not just leak info every month to get free advertising. With all this "hype" they'll flop having nothing short of near i7 performance.

With the IMC off the same die as the cores, it would need to run faster to overcome operational latentcy, and less heat present would allow it to run faster, however this is just a lame duck chip with the "proof in the pudding" as the integrated video. How much heat can we put in one chip? Is/was that the limiting factor on overclocking the FSB on the I7 series, or how fast the electrons can move in and out of a large die? I have a feeling this is the first step back for Intel to make a few steps forward in the future. Not that it is a bad chip, but realise it with the current integration will suffer on a few fronts, namely those we at this site care about. FPS, and scores.

 

[Hayder_Master]

im very confused about this new technology from intel , all i can say if this have lower performance than AMD cpu im goona sing to intel "lose your self" song

 

[FordGT90Concept]

http://img.techpowerup.org/090426/Capture091.png

Capiche?

The most likely explanation for Clarkdale's design approach is because the IGP needs memory, and the best way to have some, is by having a memory controller next to you.

QPI is a completely different beast. Most likely, the IMC has its own QPI (or at least reserved quadrants of QPI) so as long as the IMC is on the same chip, it should make virtually no difference in performance.

That is, the IGP makes requests to the IMC the same way the cores do (via QPI). QPI is literally a computer on a single chip (all MCM like). Lemme try to map out what makes sense to me...

Name|Core|North Bridge|IGP
Bloomfield|Type A|Off-Die|N/A
Lynnfield|Type B|MCM|N/A?
Clarkdale|Type B|MCM|MCM

Type A = High IPC, Tri-Channel memory controller.
Type B = Low IPC, Dual-Channel memory controller.
MCM = Multi-Chip Module (not integrated in to the core but integrated under the IHS)
? = Not sure if the door is left open to a third party (like VIA) to make a IGP or not.

There's no reason to believe the actual processor cores in Lynnfield/Clarkdale are different in any way just as a Core 2 Duo hooked up to a G43 or a P45 makes no difference to the processor. Likewise, how a AMD 6000+ hooked into an 790GX vs a 790 FX makes no difference to the processor. To the processor, it is no different than having a 4870 in a PCI Express slot--just something else to nag it for data.

Think of QPI is an FSB that is point-to-point instead of shared. That makes the processor a mini motherboard.


Hmm, don't think I can add anymore than that. XD

 

[Assimilator]

i5 uses DMI, not QPI, as many of the screenies in this thread show... could you please change the text of the article to reflect this?

 

[btarunr]

i5 uses DMI, not QPI, as many of the screenies in this thread show... could you please change the text of the article to reflect this?

Do you see the QPI between the CPU and NB dice on the processor? DMI is not the system bus, it's the chipset interconnect.