“Say what! Another processor?” Well, yeah, what else are they going to do over at Intel. Someone is always actively looking for good ways of making current generation processors better. Of course, these are just the ones we know about. When they’re not busy launching a processor, they’re busy working on other projects like fine tuning their DP55KG, or DP55WG motherboards. Today, we get to see a tweak in their processors which include a new Core i5-655K and Core i7-875K “K Series” processors. Trickling down some tech from their top end chips (and aiming straight at AMD Black Edition parts) the new processors offer some multiplier unlocking goodness at a more affordable price. Let’s see how they perform!
K-Series Processor Features and Specifications
Chances are that you’re familiar with the LGA1156 processors we covered over the last year as well as their most common features. But, the biggest change to the Core i5 32nm Clarkdale and i7 45nm Lynnfield processors is their “unlocked” multipliers. More on that in a minute.
The most familiar differences here are that the Clarkdale contains an integrated graphics processing unit where the Lynnfield does not. The Core i5-655K is currently the perfect processor for home theater PCs especially when coupled with an H55 or H57 motherboard. The Core i7-875K is best suited for mainstream and even pro-users who have need more computational power.
Intel DP55KG Extreme and DP55WG Media Motherboards
INTEL has made some adjustments to their motherboards in anticipation of unlocked multipliers. Since the Core i7-875K is a power user processor, it would be best suited for Intel’s DP55KG motherboard while the Core i5-655K is a good budget solution and matches well with the DP55WG motherboard.
If you aren’t familiar with these parts, both boards support many of the same features including ATI Crossfire and NVidia SLI. In fact, both are nearly identical except when it comes to expansion slots and overclocking. They both offer the Realtek ALC889 audio Codec which means quality should be siilar in movies or video games.
We’ve written a comprehensive review of the INTEL DP55KG motherboard if you want to see what it is capable of. If you already have one, remember that your DP55KG will require a very easy BIOS update where as the more current INTEL DP55WG does not.
A Closer Look at Unlocked Multipliers
The processor’s multiplier is often called the clock multiplier or bus/clock ratio. You’ll find this setting located in your motherboard BIOS. The latest motherboards list the setting as Base Clock Control, CPU Ratio Setting, and CPU Bus Clock.
Stock Multiplier at 22
Overclocked Multiplier at 30
As we mentioned, the “K” in the processor name signifies that the revised processor has an unlocked multiplier which can easily be increased from stock settings. This overclocks the processor very easily, often without manipulating voltages on both extreme and regular motherboards. The typical INTEL processor have the multipliers locked at the factory and can only be incremented downwards. Increasing the multiplier on regular motherboards is often less successful due to the BIOS (or processor) limitations.
The benefit here is that even budget motherboards very often accept the increased multiplier settings as though it’s a stock processor. So, it’s safe to say that both the Core i5-655K and i7-875K will easily satisfy all forms of users especially overclocking enthusiasts. Either way, everyone wins.
Installation Notes and Test System setup
A small group of motherboards were used mainly to test whether or not the CPUs are truly supported. There’s nothing worse than getting a new processor that isn’t supported by a motherboard. We used a GIGABYTE GA-P55A-UD6, ASUS P7P55D Pro (yep an older model), and both Intel DP55KG/DP55WG motherboards for a quick check up.
While it’s not surprising to see the newer P55A boards supporting the K series, older boards often get left in the cold. ASUS was very quick to extend support even to the older P55 motherboards which we took for a spin or two around the track a while ago. The 1702 BIOS revision provided by them worked just fine.
Here’s the break down list of our test system and components:
- CPU 1: Intel Core i5-655K Clarkdale Processor
- CPU 2: Intel Core i7-875K Lynnfield Processor
- CPU 3: Intel Core i5-650 Clarkdale Processor
- CPU 4: Intel Core i7-870 Lynnfield Processor
- Motherboard(s): Intel DP55KG and DP55WG Motherboards (stock benchmarks)
- GIGABYTE GA-P55A-UD6 Motherboard (overclocking)
- Memory: Patriot Memory Sector5 2400MHz Dual Channel DDR3 Memory
- Video Card: ZOTAC GTX285 1GB Infinity Edition Graphics Card
- Power Supply: Antec CP-850 Watt Power Supply
- Cooling: Koolance CPU-360 and Exos 2.5 Liquid Cooling
Once again, Intel Turbo Tech was enabled during basic benchmarks being that it’s a CPU feature. It was only disabled during our attempts to reach insane frequencies to ensure stability.
Overclocking Is Easy!
Both the Core i5-655K and Core i7-875K processors offer a multiplier increase of 6 over their stock setting. That’s an easy overclock for any novice. Of course, manual overclocking was much more productive. Our 875K was just a bit less than eager to follow the 870 processor on the way to 4.5GHz. The 875K would just hit 4.4GHz and required much more VCore voltage as well as a little extra push from the board.
However, the 655K was more eager to top 4.5GHz and would probably go higher with more time. This particular 650 test processor just couldn’t keep up even with more drastic measures. Still, it’s a healthy overclock nonetheless in both cases. Any user should be happy as long as it’s paired up with a good motherboard.
Benchmarks
This latest onslaught of test applications included SANDRA CPU, SANDRA Memory Bandwidth, Cinebench R11.5, 3DMark Vantage, Unigine Heaven Demo, Crysis Warhead, GraySky x264 HD Benchmark 3.0, and PCMark Vantage.
SANDRA Math and Multimedia
These scores are indicative of having good platform support. These two chips are fully capable of more than just stock performance. They should make a big difference when working with media files. Makes you want a Core i7, doesn’t it?
SANDRA Memory Bandwidth
Holy bandwidth Batman! With a little overclocking, we saw what the 875K could do with capable dual channel DDR3 memory. This will help increase performance in some applications with large files.
Cinebench R11.5
It’s another even race to the finish. The K series does offer just a tiny more underneath the hood though it isn’t quite obvious. But we’ll take the free performance boost.
3DMark Vantage
The results here aren’t surprising. We’ve got nearly identical cores except two are unlocked. What is nice to see is that even though the Core i5 processors are short 4 threads, they still keep within shooting distance of the Core i7 series. Who ever said they’re weak has no concept of innovation.
Unigine Heaven Demo
This has fast become one of the top 5 favorite 3D benchmarks due to its great DirectX support. Even though we used a DX10 graphics card, you can still get an idea of the kind of support you can get from the K series stock or overclocked.
Crysis Warhead
There’s no question that these are playable frame rates even at high settings. Even a little overclocking benefits the results. Sure, these processors can game. But, can you?
x265 HD Benchmark 3.0
We all love to encode some movies. If you’re a media-phile, then the Core i7 series is for you. When overclocked, these two chips offer some even greater performance.
PCMark Vantage
Well, here we see that the extra cores and Hyper-threads do make a difference. We see that the 875K is obviously scores better due to the extra cores in gaming and productivity. But, as you saw in the game benchmarks, it doesn’t always equate in to a real world benefit for single threaded games.
Final Thoughts
It’s nice to see some unlocked processors coming from Intel again that don’t carry the Extreme Edition price tag. The $220 Core i5-655K and $190 Core i5-650 are currently about $30 different between price tags which we feel is well worth the extra cost. But, the real money is saved when buying the Core i7-875K processor.
At $350 USD, it’s easily a $150 less than its Core i7-870 sibling which still carries a $500 or more price tag. This is by far your best bang for buck if you’d like a system that will last you for years to come.
What the Core i5-655K and Core i7-875K processors offer is simplicity for the enthusiast in us all dying to get out. Everyone can be an overclocker without having to do much more than increasing one setting in the BIOS, or in the overclocking software bundled with your motherboard. Either way, you don’t have to be a BIOS guru to get some respectable performance gains.
With good pricing, guaranteed performance, and processing power for media and gaming, we foresee the K Series processors emptying off the shelves pretty quick.
Pros
- Unlocked multiplier
- Very easy to overclock
- Works with both P55 and H55 chipsets
- Core i5-655K worth the extra money
- Core i7-875K “Best Bang for Buck”
Cons
- You’ll have to install it yourself 🙂
Overall Rating: 9.0/10.0
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Intel Core i5-655K Clarkdale and Core i7-875K Lynnfield Processors – Photo Gallery
