Intel’s Core i5-655K & Core i7-875K: Overclocked and Analyzed
by Rajinder Gill on May 28, 2010 5:00 AM ESTi5-655K Meets a Cold Snap
Our dual rotary cascade is capable of holding -108 Celsius temperatures under full load from a Clarkdale processor clocked to 5.9GHz. For the i5-655K we’re kicking-off with Vantage:
Almost 200MHz behind the i5-661 in this test and around 100MHz behind our retail i5-540. Luckily for the i5-655K, this particular benchmark is not high on most peoples' agenda for Clarkdales. The real fun zone is Super Pi 32M:
Again, this comes in behind the i5-661, by around 250MHz this time. There’s nothing additional that the i5-655K offers over our 661 by virtue of its unlocked multipliers – at least up to this temperature. We tried various methods to squeeze more frequency and more performance out of the i5-655K, but were unable to find a better operating point than what we’ve shown here. QPI frequency is limited to around 4.8GHz on this sample, so the only way to really get the best from the chip is to keep QPI close to this level and provide a reasonable amount of memory access latency around the DDR3-2000 mark.
There is a bit of a reprieve for the i5-655K against the i5-540 however, because although the i5-540 manages 6GHz in this benchmark it scores poorly due to a maximum 23x multiplier needing a high BCLK frequency and thus a low QPI ratio to achieve this speed. As such, based upon everything we've seen here, our conclusion is that the performance of this particular i5-655K very much fits its price. There’s certainly enough on-tap to edge out the lesser i3 series in key areas, but we've not seen enough to believe they'll knock the better i5-660+ samples off the podium.
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wavetrex - Friday, May 28, 2010 - link
In the table it sais $284 for the 980X, that MUST be a mistake!mianmian - Friday, May 28, 2010 - link
In a previous Anandtech aritical, it was $999, maybe it is $824 nowTexpat - Friday, May 28, 2010 - link
I think the price for the 980x might be wrong. $1,000 would be closer tot he truth.ltcommanderdata - Friday, May 28, 2010 - link
I'm really pleasantly surprised that the 2.93GHz Core i7 875K at $342 is cheaper yet has more features than the 2.93GHz Core i7 870 at $562. Although I'm guessing that's only temporary as the upcoming 3.06GHz Core i7 880 will probably take over the $562 price point, with the Core i7 870 dropping down to $284 and the Core i7 860 being phased out. There's also a Core i5 760 to replace the Core i5 750.DrMrLordX - Friday, May 28, 2010 - link
You guys really busted out the big guns with the dual-stage cascade! Please do this more often when overclocking. I would love to see a C3 Propus at -100C (or a Thuban).jleach1 - Friday, May 28, 2010 - link
On the second page, i believe in the 'test rig' table the proc is listed as a i5-870 instead of the i7-870Rajinder Gill - Friday, May 28, 2010 - link
Thanks - fixed!GeorgeH - Friday, May 28, 2010 - link
"it’s full of talk about voltages and harps on about overclocking"No need to be shy about that - Anandtech is bookmarked because of awesome articles and analyses like this one.
FlanK3r - Friday, May 28, 2010 - link
not bad, my x6 1090T is full stable 4300MHz 2800MHz NB with aircooling ,-)...for games and benchmarks 4400-4450 MHz :)AstroGuardian - Friday, May 28, 2010 - link
Guys, i think you should not hurry to release articles instead of taking them slow and sure. Many typos especially in the graphs.i3-530 vs i5-540