Intel K Series Processors

Conclusion

Intel K Series  Processors

Conclusion

i7-875K

It's a curious set of results that aren't too easy to read much into. Some tests it came out looking very good at stock speeds, and others it really struggled with.

The thing that makes this hardest to understand is that to all intents and purposes it is a i7-870 with an unlocked multiplier. The 870 we know is an absolutely monster chip so we should see some fabulous results.

Our overclocking results even backed this up to some degree with 4.4 GHz maximum and 4.28 GHz stable, it should be a powerhouse. It certainly topped all our synthetic graphs to a greater or lesser degree. Then you look at the results of real world testing and the gap shrinks immensely. Once you move into gaming even when overclocked the gap has entirely disappeared and it's not even heading the pack.

It doesn't make any sense, but then you realise the i7 870 retails at around £420, and this i7-875K retails at around £310. It can't be purely an improvement in manufacturing process that accounts for the difference. Our 870 will do 200BCLK all day long, whereas the 875K really hates anything much about 170. So somehow a little jiggery pokery has gone on. After all if Intel sold a chip that was the same as one £110 more, but with the possibility to run 26x200 for 5.2GHz, it would be a bit of an own goal.

We just can't see the niche this fills. For £90 less you can have the brilliant i7-930 and that saving will be enough for the slightly higher price a X58 motherboard and the extra stick of RAM will be. Although of course triple channel RAM isn't a necessity. Or for £80 less you can get the i7-860 on the LGA1156 platform and use that saving towards something else, because the performance will be roughly the same. It's priced as a bargain 870, with the performance of an 860.

Good. Just not great.

i5-655K

As for the 655K, whoo what an overclocking beast. It's not often we stop and stare at an overclock, but when a processor that comes out the box at 3.2GHz is 100% stable at cool at 4.4GHz, and easily hit 4.7GHz, you do have to take a step back and bow before greatness.

Naturally there are a few things to mention that aren't overclocking related.

Firstly it comes with an integrated GPU. This would under normal circumstances make it ideal as the basis for a office or video rig. However the main problem with that line of thinking is that it's retailing at a whopping £200. The i5-650 is only around the £160 mark, so you're paying a £40 premium for those unlockable multipliers. Even worse the quad-core i5-750 is also around £160 and that is nearly as much of an overclocker. So you have the choice of dual-core with hyperthreading on the i5-650, or quad core without, both for £40 less. Both will do 4GHz happily. So it's certainly pricier than we were hoping.

Secondly, at stock speeds it's not exactly amazing. Sure it's fine in gaming because we paired it with a beefy graphics card and most games are more about the GPU than the CPU. But even the most application phobic amongst you will use your PC for more than just loading games. That's where the speed difference counts.

However, if what you want is a good starting point on the overclocking adventure, or you mainly play games and don't mind having to overclock to get the best out your system, it has excellent performance. It's also very cool thanks to the 32nm process, and those AES instructions mean that any encryption you have to do will be like lightning.

We'd prefer to see it a little cheaper, but for its overclocking performance it has to win our OC3D Performance award.

All in all a couple of good chips that are a little pricier than we'd hoped to see and therefore quite hard to pin down exactly where they fit in the Intel line-up. i5 is the budget option, and the 655K isn't, and i7 is the performance king, but the 875K isn't that either.

i7-875K

i5-655K

Performance   Award  

Thanks to Intel for the samples today, discuss our findings in the forums.

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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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