Clarkdale specs

Core i5-661

Bottom of the CPU

Clarkdale on left, Lynnfield right

Meet the Clarkdale family

While the focus of today’s article is on the Core i5-661 CPU only, Intel’s introducing 12 new Clarkdale CPUs this week, of which the Core i5-661 is one of them.

On the desktop, Intel’s launching six new Clarkdale CPUs on January 7. Four of the new processors are designated under the Core i5 brand, with the range including the Core i5-670, Core i5-661, Core i5-660, and Core i5-650. Two new Core i3 CPUs are also being introduced, the Core i3-540 and the Core i3-530. Later this quarter, Intel will also be rolling out a new Pentium G6950 CPU that’s based on Clarkdale.

For mobile users, Intel is introducing 6 new Arrandale CPUs, including four Core i5s (the Core i5-540M, Core i5-520M, Core i5-520UM, Core i5-430M) and two Core i3s (the Core i3-350M, Core i3-330M).

To run alongside the new processors, seven new chipsets are being introduced this week, with the Q57, H57, and H55 being offered for desktops, and the QS57, QM57, HM57, and HM55 chipsets being offered for notebook PCs.

Also being introduced this week are five new Core i7 mobile parts based on Intel’s Arrandale core.

All of the Clarkdale CPUs are based on the same Nehalem architecture first launched by Intel in 2008. Key Nehalem features like the integrated memory controller, L3 cache, Turbo Boost (in the case of Core i5 CPUs), and Hyper-Threading are all carried over. Intel’s merely scaled the number of processing cores down to two, chopped the L3 cache in half (down to just 4MB L3, versus 8MB in Lynnfield), and added graphics capability to the CPU, negating the need for a dedicated graphics card.

Physically Clarkdale is a 2-chip solution, with one chip consisting of the 32-nm CPU die, which measures in at 81mm2 with 383 million transistors. In comparison, Lynnfield’s die size is over 3X larger: 296mm2 with 774 million transistors, while Bloomfield’s die is 233mm2 with 731 million transistors.

The second chip in Clarkdale is made using Intel’s 45-nm manufacturing process. This chip contains the PCI Express (16 lanes), dual-channel memory controller and graphics core and measures 114mm2 with 177 million transistors. You can see what a Clarkdale processor looks like underneath its heatspreader here:

And here is what the CPU die itself looks like (with accompanying block diagram mapping out where everything is located on the die):

Intel's Clarkdale Desktop CPU Lineup
As of January 7th, 2010
CPU	Stock Clock Speed	Max Turbo Speed	# of Processing Cores/Threads	L3 Cache Size	Memory Speed Support	Max TDP	Price
Core i5-670	3.46GHz	Up to 3.73GHz	2/4	4MB	DDR3-1333MHz	73W	$284
Core i5-661	3.33GHz	Up to 3.6GHz	2/4	4MB	DDR3-1333MHz	87W	$196
Core i5-660	3.33GHz	Up to 3.6GHz	2/4	4MB	DDR3-1333MHz	73W	$196
Core i5-650	3.2GHz	Up to 3.46GHz	2/4	4MB	DDR3-1333MHz	73W	$176
Core i3-540	3.06GHz	N/A	2/4	4MB	DDR3-1333MHz	73W	$133
Core i3-530	2.93GHz	N/A	2/4	4MB	DDR3-1333MHz	73W	$113

Notes

One new addition that’s been added to Clarkdale that isn’t mentioned in the chart above is AES-NI (Advanced Encryption Standard-New Instructions). These are six new instructions that have been added to potentially speed up applications that use the AES algorithm for encryption and voice-over-IP. Popular examples of real-world apps that use AES include Windows bitlocker encryption and Winzip.

Unfortunately, Clarkdale’s Turbo Modes aren’t as aggressive as Lynnfield’s. Clarkdale CPUs can automatically OC themselves up to two speed bins, so in the case of the Core i5-661, up to 266MHz over the CPU’s stock frequency of 3.33GHz. With Turbo Mode, Lynnfield processors can be OC’ed up to five speed bins in apps that are single or dual-threaded (of course provided that the CPU remains cool and power consumption remains in check).

As a result, Clarkdale CPUs won’t be able to encroach too much on Lynnfield when it comes to performance, even though the i5-661 and i5-670 have a clock speed advantage over Intel’s fastest Lynnfield processors.

Wondering what the difference is between the Core i5-661 and the 660 part? For the 3D performance-minded, the Core i5-661 sports a faster 900MHz graphics core, while the other Clarkdale CPUs rely on a graphics core that runs at 733MHz. This results in a slightly higher TDP, but should allow the 661 to outrun the other processors in 3D apps.

The Core i5-661 also lacks support for Intel’s Trusted Execution Technology (although some will probably see this as a bonus), vPro and VT-d.

Intel HD Graphics

Speaking of the graphics core, as we mentioned earlier this isn’t a next-generation leap over G45. Intel continues to rely on the same basic DX10 graphics core as before, only it’s been tweaked to offer better audio/video capabilities for the HTPC crowd (including native support for bitstreaming Dolby TrueHD and DTS-HD), and sports two additional shading units and higher clock speeds for 3D (up to 900MHz in the case of the Core i5-661). We’ve included a few slides from an Intel preso that highlights the new features that have been added to Clarkdale’s graphics core:

Since this isn’t an all-new graphics core, 3D performance is improved, but not to the extent where cutting-edge games like Crysis suddenly become playable. Even with the lowest graphics settings, Crysis is still a slideshow.

Intel’s never targeted their IGPs toward the hardcore gamer though, instead their goal is to deliver just enough 3D performance for the mainstream and casual gaming crowd who’s playing titles like Sims 2/Sims 3, Spore, or Rollercoaster Tycoon.

That didn’t stop us from running a few benchmarks with Far Cry 2, Resident Evil 5, and Crysis though.