What's the technical difference between the i3, i5, and i7?

[Rakehellion]

Is an i5 just an i7 without Hyperthreading?

 

[NTMBK]

A standard i7, yes. The i7-E parts are different as they are based on Xeon chips.

 

[Sable]

Is an i5 just an i7 without Hyperthreading?

On the desktop, yes. Plus a 100mhz speed bump.

And i3 is 2 cores with hyperthreading.

 

[nwo]

In addition to hyper threading and slightly higher base clock speed, desktop i7s also have (2MB) more cache than desktop i5s.

 

[Rakehellion]

So they're identical in single-threaded performance?

 

[Rakehellion]

A standard i7, yes. The i7-E parts are different as they are based on Xeon chips.

How is the i7-E different? Does it support ECC and multi-processor configurations?

 

[nwo]

So they're identical in single-threaded performance?

Not necessarily. They have different clock speeds as well as varying amounts of cache size, both of which are a significant impact to single threaded performance.

 

[nwo]

Oh and also, i3s do not have turbo boost while i5s and i7s do, which is probably the biggest impact in single threaded performance. If you are using only 1 core on an i5 or i7, you will get max turbo speeds.

Here is a decent benchmark of relative single threaded CPU performance:
http://www.cpu-world.com/benchmarks/Intel/Core_i3-4340_single.html
http://www.anandtech.com/show/4083/...core-i7-2600k-i5-2500k-core-i3-2100-tested/17

Keep in mind that each generation uses a different architecture, which is roughly 5-10% faster than the previous generation running at the same clock speeds.

 

[NTMBK]

How is the i7-E different? Does it support ECC and multi-processor configurations?

I'm not certain about ECC, but multi-processor configurations are not possible with the i7-E. Intel has disabled the QPI links required to communicate between sockets.

The i7-E is the current generation workstation processor, with a few cores disabled. This is why you can get it with up to 6 cores- Ivy Bridge E Xeons can go from 6 to 12 cores. However the core is an older design than the consumer, not E series i7. For instance while the 4770k has 4 Haswell cores, the 4930K has 6 Ivy Bridge cores; the 3770K had 4 Ivy Bridge cores while the 3930k had 6 Sandy Bridge cores; and so on.

 

[zir_blazer]

Intel likes to disable ECC support on the consumer Desktop parts. Actually, Haswell do support ECC. You have the Xeon E3 line, which the latest parts use Haswells dies identical to Core i5/i7, but these do support ECC.

 

[Arkaign]

Desktop :

Celeron / Pentium : Dual-Core with Smallish Cache 2C/2T
i3 : Dual-Core with Hyperthreading 2C/4T
i5 : Quad-Core 4C/4T
i7 : Quad-Core with Hyperthreading 4C/8T
i7 2011 : up to Hex-Core with Hyperthreading 6C/12T

Notebook :

ALL OVER THE PLACE. They literally have sub-2ghz "i7" parts that are just dual core w/HT.

 

[crashtech]

The desktop i3 is like half of an i7 with no Turbo.

I think it is close enough to say that an i5 is like an i7 with no HT, though there are some other minor differences.

 

[Bubbleawsome]

I'm not certain about ECC, but multi-processor configurations are not possible with the i7-E. Intel has disabled the QPI links required to communicate between sockets.

The i7-E is the current generation workstation processor, with a few cores disabled. This is why you can get it with up to 6 cores- Ivy Bridge E Xeons can go from 6 to 12 cores. However the core is an older design than the consumer, not E series i7. For instance while the 4770k has 4 Haswell cores, the 4930K has 6 Ivy Bridge cores; the 3770K had 4 Ivy Bridge cores while the 3930k had 6 Sandy Bridge cores; and so on.

Sorry to derail a bit, but what were the 9xx series then? And was there a 29xx series? I've never seen one. What happened there?

 

[Yuriman]

Sorry to derail a bit, but what were the 9xx series then? And was there a 29xx series? I've never seen one. What happened there?

With Sandy Bridge, Intel basically split socket 1366 into two lines: 2011 and 1155. As an example, the 920 had triple channel memory, while SB had dual channel and SB-E had quad. I'd argue that SB-E should have been called 29xx because it's a second-generation i7, but it's all in the marketing.

 

[Rakehellion]

So the i3 has HT, no Turbo. The i5 has Turbo, no HT. i7 has both.

Except this mobile i5 and i7 look nearly the same.

 

[crashtech]

Figuring out Intel's mobile line is a joke.

 

[RU482]

Figuring out Intel's mobile line is a joke.

yeah no kidding. take everything you know about their desktop CPU naming scheme and throw it out the window. Also, WTF is up with BayTrail Pentium and Celeron SKUs AND Haswell Pentium and Celeron SKUs? Are they emulating NVidia's naming practices?

 

[crashtech]

Honestly I don't mind looking up the specs of any given CPU to familiarize myself with the intended product, it's just that so many vendors can't seem to be bothered to accurately list what the thing has in it, and act like you are from outer space for insisting upon having accurate info...

 

[zir_blazer]

So the i3 has HT, no Turbo. The i5 has Turbo, no HT. i7 has both.

Except this mobile i5 and i7 look nearly the same.

Core i3s are Dual Cores, Core i5 are Quad Cores. There is a huge difference there.


Wikipedia has sorted out quite well the naming issue. They have a few, organized tables based on specs instead of mere naming:

List of Sandy Bridges
List of Ivy Bridges
List of Haswells

 

[Bubbleawsome]

With Sandy Bridge, Intel basically split socket 1366 into two lines: 2011 and 1155. As an example, the 920 had triple channel memory, while SB had dual channel and SB-E had quad. I'd argue that SB-E should have been called 29xx because it's a second-generation i7, but it's all in the marketing.

What was it based off of though? From what I can tell the i7 9xx was separate from anything else, then they skipped the 29xx, then named all future x9xx series one ahead of the true architecture.

 

[NTMBK]

Honestly I don't mind looking up the specs of any given CPU to familiarize myself with the intended product, it's just that so many vendors can't seem to be bothered to accurately list what the thing has in it, and act like you are from outer space for insisting upon having accurate info...

"Hi there sir, can I help you today?"

"Yes, I'm interested in this laptop. Could you tell me what processor is in it?"

"Sure thing, it's an i5."

"Yes, but what specific model number?"

"...it's an i5."

 

[coffeejunkee]

What was it based off of though? From what I can tell the i7 9xx was separate from anything else, then they skipped the 29xx, then named all future x9xx series one ahead of the true architecture.

They already split desktop lines with 1366 and 1156 (although it took a while for 1156 to appear). Before that mainstream and high-end used same socket (P45 and X48). Then they did a Worldcom with SB-E: can't sell previous generation cpu to enthusiasts if it has a lower number.

So the i3 has HT, no Turbo. The i5 has Turbo, no HT. i7 has both.

Except this mobile i5 and i7 look nearly the same.

For desktop it's consistent and easy to understand. For mobile not so much. Only difference between between i5 and i7 is more cache for the latter.

 

[piasabird]

Just go to www.intel.com and compare 3 CPU'S using ARK.
You will see things like Cache Size, Number of physical cores and threads it can run, the Wattage ratings, the thickness of the die layers, The type of HD Video, and maybe how turbo boost works. There are differenced between i3,i5 and i7. Plus there are differences between just 2 i3 chips.

As an example some i3 processors have 3meg cache and some have 4meg cache and a better version of HD Video.

The problem is it is hard to tell what is better without a benchmark. Then the thermal footprint may be more important.

I like that chart, but I wonder if a lay person can look at the chart and know how to evaluated it or how well each processor actually responds and performs when tested.

I guess a lot depends if you have software that will actually take advantage of specific processor attributes.

 

[SPBHM]

Core i3s are Dual Cores, Core i5 are Quad Cores. There is a huge difference there.


Wikipedia has sorted out quite well the naming issue. They have a few, organized tables based on specs instead of mere naming:

List of Sandy Bridges
List of Ivy Bridges
List of Haswells

all desktop i5s do have Turbo, some are dual core with HT, most quad core with no HT, but not all,
examples of i5s Dual Core with HT: i5 650, i5 2390t, i5 4570T.

all i3s are dual core with HT and no Turbo, be it for desktop and mobile,
all mobile i5s are dual core with HT and Turbo I think,
and some mobile i7s are dual core with HT (but more l3 cache and higher clock), and others quad core (with HT and Turbo always)

 

[Concillian]

This depends entirely on the market segment you're talking about.

In ULV notebook an i7 can be a dual core w/HT, in Desktop it can be a quad or more core with HT. Some i5s have HT in some segments.

In socketed CPUs, yes, usually 15 is a quad without HT and an i7 is a quad with HT, but Intel seems to move around what i5 and i7 mean depending on the generation. There is no set rule that applies to all i3 / i5 / i7. Think of them as generic terms of good / better / best, but only within a given target market segment.