Summary: With a 3.33GHz stock clock speed, integrated DX10 graphics core, and 32-nm manufacturing process, Intel's Core i5-661 is designed to make Core 2 Duo obsolete. But does it accomplish its mission? See how it performs with and without its integrated graphics in today's article!
Thanks to their new architecture (which shared many similarities with AMD’s latest processors), these CPUs blew the doors off the fastest Core 2 CPUs, and did so while remaining energy efficient.
Upgrading to one of these CPUs wasn’t cheap though. A motherboard based on Intel’s X58 chipset is required, and as anyone who’s ever shopped for an X-series chipset can tell you, these extreme motherboards can get pretty pricey. Even today a stripped-down X58 motherboard usually goes for $170-$200, while midrange boards sell for $250+. A fully loaded X58 motherboard is priced over $300.
Therefore in order to appeal to the more price conscious crowd, Intel introduced their first mainstream CPUs based on the Nehalem architecture last September. These CPUs are based on Intel’s “Lynnfield” core and are designated as the Core i5-750, Core i7-860, and Core i7-870.
With their aggressive Turbo Mode settings and large cache, these CPUs were able to deliver the same blazing performance we saw from Bloomfield at the end of 2008, but with lower CPU and platform costs. Core 2 Quad instantly became overpriced and obsolete. We’ve been recommending Lynnfield processors for all but the most demanding hardware enthusiasts and gamers.
Now Intel’s got their sights set on dual-core computing. Today Intel’s rolling out their first dual-core CPUs based on the Nehalem architecture. These CPUs rely on Intel’s “Clarkdale” core.
That’s not the only first for Clarkdale though. Clarkdale is also Intel’s first processor to utilize their brand new 32-nm manufacturing process. Historically Intel has reserved new process introductions exclusively for their high-end CPUs where volumes are lower; this allows them to work out any kinks in the process without potentially running into supply issues.
However, Intel’s so confident with their 32-nm process they’re starting with the high-volume parts first; Intel’s 32-nm CPU for the high-end segment, the 6-core Core i7-980X “Gulftown”, isn’t expected to debut until Q2’2010.
Clarkdale’s 32-nm manufacturing process isn’t the CPU’s most dramatic new first though. That honor goes to its integrated 3D graphics core, which is built into the same package as the CPU.
Integrating graphics into the CPU is quite a coup for Intel. It wasn’t long ago that we expected AMD to finish first here…
The race to bring 3D graphics to the CPU
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.
And here is what the CPU die itself looks like (with accompanying block diagram mapping out where everything is located on the die):
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.
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.
Because we’re a site that’s focused towards the middle and high-end gaming crowd, we knew from the outset that we wanted to focus on the Core i5-661’s performance as a potential replacement for the Core 2 Duo E8500 (which it’s priced similarly to), rather than its integrated 3D graphics performance.
We know that the majority of our readers are going to want to know which is faster: the E8500 or the Core i5-661, both paired with a discrete graphics card like the Radeon 4890 or GeForce GTX 275, but we still wanted to see how the Core i5-661’s integrated graphics performed with a few of today’s latest games. Let’s have a look shall we?
Far Cry 2
Resident Evil 5
Intel Core i5-750
Intel Core i5-661
Intel Core i5-661
Intel DH55TC (H55 Motherboard)
Intel Core 2 Duo E8600
Intel Core 2 Duo E8500
Intel Core 2 Quad Q8400
ASUS P5E3 Premium
4GB (2x2GB) OCZ Platinum @ DDR3-1333 Speeds
NVIDIA GeForce GTX 275
500GB Western Digital Caviar SE16
Windows 7 Ultimate 64-bit
Resident Evil 5
We’re going all-Intel for today’s CPU article.
Valve Particle Simulation Benchmark
Far Cry 2 – Direct3D
Crysis – Direct3D
Resident Evil 5 – Direct3D
World In Conflict – Direct3D
Armed with Gigabyte’s P55-UD4P, we were eager to see how far we could push our Core i5-661 CPU. With a simple BIOS update, the Gigabyte board was easily able to handle the Clarkdale CPU, and we proceeded to take it up to 3926MHz on stock voltage, the highest of any Nehalem CPU we’ve tested yet.
Unfortunately, we weren’t able to get much further than that, topping out at 4025MHz. It’s possible that the P55 motherboard’s BIOS needs more fine tuning when it comes to Clarkdale OC’ing, or we may have received a sample from Intel that just doesn’t want to OC. Our OC on stock voltage suggests that the CPU should be able to scale much further with higher voltages, but we just couldn’t get the system to run with complete stability at higher speeds. We’ll have to re-examine this topic once newer BIOS is available.
For over a year now the E8600 has been regarded as the world’s fastest dual-core CPU. With the debut of Clarkdale, that reign is now over. The fact that it’s able to do this while also integrating a more powerful graphics core is an impressive accomplishment. While Clarkdale isn’t up to the task of running Crysis comfortably, the new audio/video features Intel has added to Clarkdale should make it perfect for HTPC use. Simply drop the processor into an H55 or H57 motherboard and you have an instant home theater PC for just under $300. The Dells and HPs of the world could also use Clarkdale to build some pretty intriguing all-in-one PCs.
These are the two most intriguing scenarios that we see for Core i5 on the desktop at this time. Due to its high $196 price tag, Core i5-661 Clarkdale really doesn’t make much sense anywhere else: you can get the Core i5-750 for about the same amount of money, giving you true quad-core computing and with much better performance.
Unless you absolutely must have Clarkdale’s integrated graphics, Core i5-750 is easily the better buy.
Where Clarkdale could be more compelling is on the low end with Core i3. With prices of $113 and $133, the Core i3-530 and Core i3-540 don’t encroach on Lynnfield’s price point, and although they do lack Turbo Mode support, this can easily be overcome with a little bit of OC’ing. We’ll have to try and get our hands on a chip so we can see how it compares to similar dual-core offerings from AMD, but it looks like these chips could be significantly better than the Core 2 Duo E7000-series CPUs Intel had been offering previously for the low-end segment. Right now it's looking like these could be the most intriguing Clarkdale CPUs Intel is offering at the moment.
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