Introducing Intel's Clarkdale Core i5-661

Intel's next-generation CPU arrives, ringing in the era of the integrated graphics core

In the Intel galaxy, the CPU is an inexorable black hole. A gravity well so strong that nothing can escape it as it consumes every function of the PC.

Don’t believe us? Witness add-in MPEG-2 decoders, hardware modems, hardware-accelerated soundcards, and Ethernet controllers, all of which have been swallowed by the all-powerful CPU. With Intel’s last CPU, the Lynnfield LGA1156 processor, the memory controller and even PCI-E functions were eaten by the CPU, too.

Now with Intel’s new Clarkdale (and its mobile equivalent, Arrandale) the company is taking the first step in trying to eat a gas-giant of functionality by moving a GPU core directly inside of the CPU.

But not only is Clarkdale the first Intel chip with graphics, it’s also our first glimpse at a CPU using Intel’s new, smaller-process technology. Current Core i7 and Core i5 CPUs are based on the original 45nm Nehalem design that Intel introduced more than a year ago. Clarkdale uses a newer 32nm process that is part of the Westmere family. For the most part, Westmere is an evolutionary step forward and a simple die-shrink of Nehalem, but Intel did add some interesting performance enhancements.

Read on for details about what makes Clarkdale unique.

*Graphics core runs at 900MHz

Hey, You Got Graphics in My Processor 

Until now, PC graphics have either resided in the PCI-E slot or in the motherboard’s core-logic chipset. With Clarkdale, Intel moves the GPU core directly into the CPU socket. It does this by packaging a new 45nm GPU core alongside the 32nm compute core, connecting the two via a high-speed QPI. It’s a method reminiscent of the company’s first quad-core proc, the Core 2 Extreme QX6700. Back then, Intel took a shortcut to quad-core land by combining two 65nm dual-core Core 2 Duo dies to make a “quad-core.” While chip purists scoffed that the multichip package was an inelegant hack, and AMD fanboys called it cheating, the move gave Intel a year-and-a-half lead over AMD to store shelves. (Interestingly, a parallel scenario exists today: AMD is working on its own integration of GPU and CPU, dubbed Fusion. As before, AMD’s plan is far more ambitious and elegant in its integration of GPU and CPU functionality. That product won’t see the light of day until 2011. See more on AMD’s Fusion efforts below.)

Clarkdale’s setup puts most of the logic in the GPU, which has a built-in single x16 PCI-E 2.0 controller, as well as the memory controller for both the graphics and compute core. Why use a multichip package instead of building a 32nm chip with graphics in it? It’s likely a matter of cost, technology, and timing. This move, again, gets Intel a CPU with graphics capability more than a year before AMD will deliver its version.

Got Speed?

You probably only care about one thing: How fast is the GPU inside the chip? By rough estimates, it’s about 1.5x times faster than the graphics in a current Intel G45 chipset found in most laptops and mainstream motherboards. If that sounds great, remember that Intel’s integrated graphics history hasn’t been stellar. Put plainly, Intel’s integrated graphics have stunk up the joint for years and it’s probably an insult to graphics cards to actually call Intel’s integrated parts graphics accelerators. A 3-year-old $65 discrete graphics card with a hairball jammed in the fan is slightly faster than what you get from the G45 chipset. In fact, we’ve long blamed Intel’s subpar integrated graphics for helping to push mainstream gamers to console gaming.

Intel’s reasoning is that if people are buying systems with integrated graphics, they probably don’t care about graphics. Sadly, that’s probably true. Mainstream consumers browse the web, use Microsoft Works, and don’t play anything more graphically intensive than Yahoo Bingo before heading down to the social hall for a game of bridge with Madge, Maude, and Betty.

Intel bluntly says the graphics core in Clarkdale is definitely not meant for hardcore gamers. We wholeheartedly agree. We first tested the Clarkdale using 3DMark Vantage on default and after getting a score of 0, abandoned all hope of it being capable of serious gaming.

To see if it was even capable of playing more moderate games, we fired up Left 4 Dead 2 and found the frame rate almost playable at 800x600 with the graphics set on maximum ugly. Borderlands at 1280x1024 was also over the Clarkdale’s head, but almost playable at a mobile phone resolution of 800x600. We did actually see 60fps in Counter Strike: Source at 1280x1024, with somewhat compromised graphics. Still, that’s better than nothing. As easy as it is to make fun of integrated graphics, it’s a moot point for someone who doesn’t play games.