Intel Core 2 Duo E6400 Review August 03, 2006

Introduction

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Intel had been saying for months that Core 2 would take back the performance crown from AMD when it was released, but as everyone knows, it’s PR’s job to make bold claims when it comes to performance. Practically no one outside of Intel expected Core 2 to dominate AMD’s high-end CPU lineup so thoroughly.

“But what about the lower-end Core 2 CPUs?” That’s the million dollar question a lot of you asked after seeing the Core 2 Extreme benchmarks. After all, while it’s always fun to read about $999 CPUs, not many of us have the budget to afford such a processor. Because of this, we’ve been eager to get our hands on one of Intel’s more affordable Core 2 processors. This is where the Core 2 E6400 comes in.

The Core 2 E6400 boasts many of the same key features found in Intel’s more expensive Core 2 Duo CPUs – in fact it’s built on the same manufacturing line – only Intel disables half the processor’s cache and it runs at a lower clock speed: 2.13GHz. In comparison, the Core 2 Duo E6700 runs at 2.66GHz, while the Core 2 Extreme X6800 runs at 2.93GHz. With the smaller cache and slower speed the Core 2 Duo E6400 commands a significantly lower price, just $224 compared to the $999 price tag of the Core 2 Extreme X6800 and $530 price of the Duo E6700, making it a tempting alternative to the more expensive Core 2 CPUs. In fact we can’t recall the last time a next-gen CPU launched with such affordable pricing.

With their dominance of the high-end market over, AMD quickly responded to the Core 2 threat by slashing CPU prices of their own. Whereas just a month ago the Athlon 64 X2 5000+ sold for $696, after cuts the price was reduced to $301. AMD’s new pricing was clearly intended to battle Intel’s Core 2 lineup. Here’s how the CPU market looks after this latest round of cuts:

$150+ CPU Pricing as of 8/3/06
CPU	Clock Speed (GHz)	L2 Cache Size	Price
Intel Core 2 Extreme X6800	2.93	4MB	$999
AMD Athlon 64 FX-62	2.8	2 x 1MB	$827
Intel Core 2 Duo E6700	2.66	4MB	$530
Intel Core 2 Duo E6600	2.4	4MB	$316
AMD Athlon 64 X2 5000+	2.6	2 x 512KB	$301
AMD Athlon 64 X2 4600+	2.4	2 x 512KB	$240
Intel Core 2 Duo E6400	2.13	2MB	$224
AMD Athlon 64 X2 4200+	2.2	2 x 512KB	$187
Intel Core 2 Duo E6300	1.86	2MB	$183
AMD Athlon 64 X2 3800+	2.0	2 x 512KB	$152

Note that these are the prices that distributors pay in quantities of 1,000. This is not the same as street prices. Distributors like Ingram Micro ultimately sell PC components to retailers like Newegg and Zipzoomfly. These retailers then sell the parts directly to you and me, the public. Distributors can buy in quantities greater than 1,000 and pass those savings on to retailers, this is how street prices can fall below list prices. We’re using AMD and Intel’s official list prices to keep things simple.

As a result of the cuts, Intel’s Core 2 Duo E6400 is pegged $16 below the X2 4600+. With this in mind, we’re eager to see how the E6400 stacks up against the 4600+…

The E6400 up close

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Core 2’s shared L2 cache also helps to reduce power by minimizing memory traffic.

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Overclocking the E6400

Everyone likes the idea of free performance, especially when you’re dealing with lower-end CPUs. After all, with a few keystrokes in BIOS, you can turn your “low-end” CPU into a processor capable of outperforming the latest and greatest CPUs with the right system components and a little bit of knowledge on the relationship between the CPU, front-side bus (FSB), and memory bus. That’s why we were eager to see how far we could push the Core 2 Duo E6400, and it didn’t disappoint.

We started by seeing how far we could push the CPU’s clock speed without adjusting voltage. After a little bit of work within the BIOS of ASUS’ 975X-based P5W DH Deluxe we settled on a FSB speed of 381MHz, for a CPU clock of 3.05GHz – that’s just shy of 1GHz on stock voltage! CPU temps at that clock speed topped out at 39 degrees Celsius at load.

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System Setup

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System Setup

Intel Core 2 Extreme Edition X6800
Intel Core 2 Duo E6700
Intel Core 2 Duo E6400
ASUS P5W DH Deluxe (975X)


AMD Athlon 64 FX-62
AMD Athlon 64 X2 5000+
AMD Athlon 64 X2 4600+ EE
MSI K9A Platinum (Radeon Xpress 3200)

2GB Corsair TWIN2X2048-6400C3

AMD Athlon 64 X2 4800+
AMD Athlon 64 3500+
ASUS A8R32-MVP Deluxe (Radeon Xpress 3200)

2GB OCZ Platinum DDR400

ATI Radeon X1900 XTX and Radeon X1900 CrossFire with CrossFire 6.6

Windows XP Professional with Service Pack 2

DirectX 9.0c

Benchmarks

LAME MT MP3 Encoding (MS Compiler)
DivX Converter
Windows Media Encoder 9
3DMark06
F.E.A.R. 1.05
Pacific Fighters 4.04
Call of Duty 2 1.3
Quake 4 1.2
Oblivion
SiSoft Sandra 2007
Half-Life 2 Lost Coast
Cinebench 9.5

Notes

It’s important to note that we’re running three different systems here. For testing older Athlon 64 CPUs, we’re running one Xpress 3200 platform with DDR400 and the X2 4800 as well as the A64 3500+. To test the strengths of AMD’s new AM2 platform, we’re running a second system based around MSI’s K9A Platinum motherboard. Finally, you’ll see the Core 2 CPUs running on ASUS’ P5W DH Deluxe motherboard.

Media encoding

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Microsoft Windows Media Encoder 9

DivX Converter

LAME MT MP3 Encoding

Cinebench 9.5

Notes

Intel’s Core 2 Duo E6400 excels in our media encoding tests, with the E6400 finishing 13 seconds ahead of the X2 4600+ in WME 9, while MP3 encoding is 18 seconds faster than the 4600+. The most dramatic difference between the X2 4600+ and the C2D E6400 is seen in our tests with DivX converter, where we convert a 1080p WMV-HD video into DivX format. Here the Core 2 chip finishes nearly 1 minute ahead of the 4600, in fact, Core 2 Duo E6400 even outperforms AMD’s FX-62 CPU!

The one test where AMD’s 4600+ does manage to come ahead is Cinebench 9.5. Our guess is that AMD’s clock speed advantage allows it to perform so well here. The more senior Core 2 Duo chips are able to stay ahead of the AMD CPUs in part due to their higher clock speeds and also their 4MB L2 cache.

3DMark 06

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Futuremark 3DMark05

Notes

3DMark gives Core 2 the edge in both CPU performance (by a nose) and overall performance, although even there the difference is only 2%.

F.E.A.R.

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F.E.A.R.

Notes

In F.E.A.R. Core 2 Duo E6400 outruns the X2 4600+ by 3% at 800x600, while the CPU’s pull even at the GPU-bound resolution of 1600x1200 with 4xAA/8xAF. It’s looking like the E6400 vs. X2 4600+ is a much closer race than the 4MB Core 2 Duo CPUs. Let’s take a look at performance in Quake 4 though, which has been reprogrammed to take advantage of dual-core CPUs.

When looking over the benches, it’s important to keep in mind that the 3500+ and X2 4800+ are running on AMD’s older Socket 939 platform with DDR1 memory. That explains why the 4600+ is able to keep up with the 4800+ despite having less L2 cache.

Quake 4

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Quake 4

Notes

The margin separating the Core 2 Duo E6400 from the X2 4600+ is a little greater in Quake 4, we’re looking at a 7% difference in performance at 800x600 in favor of Intel’s Core 2 CPU. While this may not sound like much, interestingly enough it’s just enough for the Core 2 Duo E6400 to squeeze ahead of AMD’s Athlon 64 X2 5000+ in our testing. By the time you hit 16x12 we’re bound by the performance of the GPU and performance across all processors is the same.

Again, as we just mentioned on the previous page (or in case you missed if it you’re using the table of contents), don’t forget that the 3500+ and 4800+ are both running on AMD’s older Socket 939 platform. Thanks to the higher memory bandwidth of DDR2, AMD’s new AM2 socket runs slightly faster than Socket 939.

Call of Duty 2

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Call of Duty 2

Notes

Call of Duty 2 just doesn’t take advantage of the faster CPUs like the previous games did, even with the latest dual-core patch.

Pacific Fighters

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Pacific Fighters

Notes

Flight sims are the most CPU-intensive game genre out there, so it was a no-brainer for us to test with Pacific Fighters, which has been patched to take advantage of SM 3.0’s vertex texture fetch feature to improve the game’s water. Here we can see where Intel’s new Core 2 CPUs really shine, with the Core 2 Duo E6400 even pulling away from AMD’s flagship Athlon 64 FX-62! Even at 1600x1200, a resolution you’d normally expect to be GPU-bound in, the C2D E6400 comes out ahead.

The AMD CPUs used to thoroughly own in this benchmark, outperforming even the fastest Pentium EE CPUs by margins of around 20-30% overall. Now Intel’s Core 2 CPUs are beating the FX-62 by a similar amount if not greater (depending on the Core 2 CPU).

Oblivion

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Oblivion

Notes

Performance is pretty similar in our outdoors testing, regardless of the processor used. Once we go into the market district of Imperial Village things begin to change though, as the area we test in contains lots of NPCs which the CPU is responsible for handling AI for. Here the Core 2 Duo managed to squeak ahead of the 4600+, but we’d call this one a draw considering the margin of error.

HL2 Lost Coast

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Lost Coast

Notes

The Core 2 Duo E6400 continues to outpace the Athlon 64 X2 4600+, although the performance difference isn’t as dramatic as what we saw in Pacific Fighters. It definitely looks like AMD’s pretty competitive performance-wise with Intel’s highest-end 2MB Core 2 Duo offering, the E6400.

SiSoft Sandra 2007

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CrossFire w/Oblivion

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Oblivion

Notes

It looks like we’re CPU-bound with Core 2 in the city area, although by 2048x1536 the margins close up slightly as the burden shifts increasingly from the CPU to the GPU.

CrossFire w/FEAR

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F.E.A.R.

CrossFire w/Pacific Fighters

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Pacific Fighters

CrossFire w/Quake 4

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Quake 4

CrossFire CoD2

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Call of Duty 2

CrossFire w/HL2 Lost Coast

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Lost Coast

Overclocking results

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CrossFire OC results

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Ballistics Report

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Pros

Performance: Intel’s brand new “Conroe” Core 2 processor core incorporates many architectural enhancements that are designed to improve the CPU’s performance. For starters, Intel’s knocked the number of pipeline stages down from 31 stages in Pentium D, to just14 stages in Core 2. This allows Core 2 to deliver more instructions per clock cycle, in essence Core 2 gives up some clock speed, but it can perform more work per clock. Core 2 can also complete up to four instructions versus three in previous processors and features more accurate branch prediction. Core 2 can also execute 128–bit SSE, SSE2 and SSE3 instructions within one clock cycle.

While it may not share all the performance-enhancing features of more senior Core 2 Duo processors such as the larger L2 cache and higher clock speeds, Intel’s Core 2 Duo E6400 is still one heckuva performer. In many cases it outperformed AMD’s Athlon 64 X2 5000+ in our performance testing, which is more expensive and runs at a higher clock speed. Overall though performance is generally 2-8% faster than X2 4600+, although the difference will vary from app-to-app, in fact Core 2 trailed the 4600+ in Cinebench.

Price: With an official list price of $224, Intel’s Core 2 E6400 is priced aggressively to move, especially when you consider the CPU’s aforementioned performance. The CPU industry has never seen prices like this before on a new CPU at launch.

Typically when a next-gen CPU is introduced like Core 2 only a few speed grades are available, and never at prices this low.


Features: Intel continues to provide support for execute disable bit and extended memory 64 technology (EM64T) with their latest Core 2 processors. If you recall, execute disable bit provides enhanced protection against malicious "buffer overflow" attacks, while 64-bit support allows the use of extended virtual and physical memory in the system. Core 2 also supports Intel’s virtualization technology. With virtualization, multiple operating systems can be run “virtually” from a single machine. Core 2 also features a 1,066MHz FSB.

Overclockability/65-nm process: While we normally don’t comment on overclocking, as mileage will vary from processor-to-processor, based on all early indications it’s looking like Core 2 is one tremendous overclocker. There are numerous reports from both independent websites as well as end users with Core 2 CPUs that are hitting some pretty high overclocks (just remember to get a third-party CPU cooler). This is due in part to Intel’s new 65-nm manufacturing process.

The smaller process allows the chip to run at lower voltages and thus consume less power while generating less heat than if a larger manufacturing process had been used. As a result, Intel (and end users it seems) are able to crank up the clock speeds pretty high for Core 2.

Cons

Availability: Core 2 CPUs have barely been on the market for a week now, so finding CPUs can be a tough task. Complicating matters is the huge demand for Core 2 CPUs right now, especially with back-to-school season now underway. OEMs are scrambling to get as many Core 2 CPUs for use in these PCs as they can, while the do-it-yourself (DIY) crowd is plucking up these CPUs as quickly as they can find them at retail.

The end result is that most retailers are out-of-stock of all but the most expensive Core 2 CPUs like the $1,000+ Extreme, and many retailers are even backordered on this chip as well.

Final Verdict

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FiringSquad says:

The extent of Intel’s victory varies depending on the application tested, in fact Core 2 Duo E6400 fell behind AMD’s Athlon 64 X2 4600+ in our testing with Cinebench. Media encoding tasks such as MP3 encoding and video encoding with Windows Media Encoder clearly favored Core 2 Duo E6400 though, as did our DivX conversion testing -- where Core 2 Duo came out over a minute ahead of the Athlon 64 X2 4600+.

In gaming, the E6400’s greatest advantage is seen in flight sims like Pacific Fighters, at 800x600 the E6400 ran 23% faster than the X2 4600+. The gap closed significantly (to within single digits) in all the other games we tested with however. Considering that the 4MB Core 2 parts were able to fairly consistently put up a double-digit performance advantage over Athlon 64 X2/FX (with the exception of a few games like Call of Duty 2), this illustrates that the smaller cache and lower clock speed found in the Core 2 Duo E6400 allows AMD to play catch up a little, although the more expensive Athlon 64 X2 4600+ is never able to completely catch up to Core 2 Duo E6400 until you hit resolutions where you’re GPU-bound like 1600x1200.

Due to that performance, Intel’s Core 2 Duo E6400 in particular should definitely appeal to CPU shoppers on a budget, hence it most definitely earns our Bull’s Eye Award for delivering such an incredible price/performance ratio. (Again, keep in mind that our pricing data is based on AMD/Intel’s official list prices, not street prices. Street prices for CPUs are particularly volatile right now, fluctuating practically on a daily basis, as both the AM2-based 4600+ and Core 2 E6400 are fairly new to the market, while the 4600+ just recently had its price slashed. In fact, street prices for the X2 4600+ are $5 lower than the Core 2 Duo E6400 at the time of this article’s writing based on information gathered on PriceGrabber.)

Once again we can’t help but feel amazed at the top-to-bottom performance of Intel’s new Core 2 CPUs. Based on all the hubbub and performance demos surrounding Core 2 at IDF, many wouldn’t have been surprised to see Intel reclaim the top performance spot, and perhaps even release two or three additional high-end SKUs on top of that, but no one expected Intel to release slower Core 2 CPUs at price points as low as $183 on launch day. AMD was forced to slash prices on their entire lineup of X2 CPUs to keep up.

As a result of these sweeping changes, it’s never been a better time to buy a new CPU. Those of you who have been on the fence about upgrading to dual-core no longer have an excuse – you can buy dual-core Pentium D 805 CPUs for less than $100 online while X2 and Core 2 Duo chips carry list prices of under $185.

For a little bit more, Intel’s Core 2 Duo E6400 delivers a nice amount of performance, and with a little bit of overclocking, you should be able to turn your 2.13GHz Core 2 E6400 into a 3GHz+ monster capable of taking down the fastest $1,000 CPUs. You can make an argument that the CPU world hasn’t seen a processor like this since the Pentium III 700E to 1GHz, or going back even further still, the beloved Celeron 300A to 450MHz. Now if Core 2 supply can just catch up to demand…