Intel K Series Processors

Technical Specifications

Intel K Series  Processors

Technical Specifications

We've got two rather different processors on test today. Thankfully with the i5 being similar to the i7 we can save you having to read tons of tables by integrating them into one.

On the left is the i5-655K and on the right the i7-875K.

StatusLaunchedLaunched
Launch DateQ2'10Q2'10
Processor Numberi5-655Ki7-875K
# of Cores24
# of Threads48
Clock Speed3.2 GHz2.93 GHz
Max Turbo Frequency3.46 GHz3.6 GHz
Intel® Smart Cache4 MB8 MB
Bus/Core Ratio2422
DMI2.5 GT/s2.5 GT/s
Instruction Set64-bit64-bit
Instruction Set ExtensionsSSE4.2SSE4.2
Embedded Options AvailableNoNo
Supplemental SKUNoNo
Lithography32 nm45 nm
Max TDP73 W95w
New AES Instructions
YesNo
Integrated GraphicsYesNo


As you can see they are both designed for fairly different markets, but roughly similar thanks to their use of the LGA1156 socket.

With the i5-655K we find it's absolutely identical to the i5-650 by being a hyperthreaded, dual-core processor with integrated graphics. One of the strange things is that the integrated graphics chip is manufactured using a 45nm process. So the processor is actually twin chip, rather than combined into a single die. This should hopefully allow us plenty of overclocking as the graphics heat wont be directly affecting the CPU die. It also, as with all 32nm Intel chips, has the new AES instruction set we first saw on the 980x. In fact the only difference is that the 655K has an unlocked multiplier.

The i7-875K is identical to the i7-870 that is the heart of our LGA1156 test system here at OC3D towers, but in a similar way to the 655K the difference is that it has an unlocked multiplier. Intel haven't adjusted anything else at all so it's still a hyperthreaded quad, on 45nm without the new AES instructions.

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Most Recent Comments

07-06-2010, 06:49:50

tinytomlogan
It's been a long while since we've seen an unlocked multiplier on a mainstream Intel. How do the K series fare?

Continue Reading

07-06-2010, 10:09:15

Steve-O-
When I finally upgrade I'll be looking for a quad-core since I do graphic work. Looks like the $930 is still the best deal. The 655 is pretty sweet though for a dual-core.

07-06-2010, 10:21:57

Diablo
Yeah, they seem expensive for what they deliver. If anyone was going to spend 300 on a CPU (or more), they would go for an X58, and clock the i7 930. The 1156 platform doesn't seem the logical place to stick these chips, although I suppose that intel don't want to put people off buying the extreme edition chips.

Good review, so good for OC3D, but weird price/platform of chips from intel.

07-06-2010, 11:05:37

AMDFTW
WOW thats extreme for aircooled over 5Ghz on water

07-06-2010, 11:06:40

tinytomlogan
the conclusion was difficult tbh as there were so many factors to consider. The 875 is cheaper than the 870 but doesnt seem as good. The 655 goes like stink but costs a good chunk more and seems expensive for a dual but it is 32nm.....

Its a tough one to call tbh.

07-06-2010, 15:09:20

Steve-O-
I hear ya Tom. Good review regardless. And I think fair scores for both.

07-06-2010, 15:16:49

FragTek
Looks good to me!!

07-06-2010, 16:19:17

Lallespasser
I think you've overlooked an important aspect. By overclocking only the multiplier, you are not forced to disable Turbo, enabling you to have an overclocked chip while still maintaining low idle power consumption. This would, at least for me, be an important factor when buying a CPU.

07-06-2010, 17:56:17

tinytomlogan
Quote:
Originally Posted by name='Lallespasser'
I think you've overlooked an important aspect. By overclocking only the multiplier, you are not forced to disable Turbo, enabling you to have an overclocked chip while still maintaining low idle power consumption. This would, at least for me, be an important factor when buying a CPU.
We overclocked the BCLK too fella as Bus speed is just as important for us, if for no other reason than to show what the cpu has to offer. 99% of overclockers are more interested in a high base clock more than a higher multiplier.

08-06-2010, 07:38:22

Rastalovich
Higher clock means faster for other componets too. An extreme cpu running at 6ghz with memory running in the 700s aint very clever.

I don't know about these offerings. The games seem to favor high(er) caches - which is weird.

31-08-2010, 05:33:10

Ari-M.
i got my 875k on the cheap....and must have scored a gem. the mem controller on my 875k is an absolute BEAST. my fill rates and latencies even surpass my x58 rig (by a staggering degree)

the 875k does fall pretty short on synthetic CPU benches....but I use it for audio production....in that environment (sample editing) memory speed trumps all....so the 875k does have an interesting little niche

it is well matched to the ASUS p7p55d
Reply
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