Core 2 Duo e4300 vs. e6400: performance on Air and Water Cooling

by Babrbarossa     |     April 19, 2007

The primary goal of this review is to investigate both the stock and overclocking performance of the e4300. For comparison, the e4300 will be tested against an e6400 CPU under three different cooling solutions: stock air, aftermarket air, and water cooling. The test platform will be based on the EVGA 680i motherboard (p26 BIOS) which has recently undergone a hardware revision for the benefit of Intel Quad-Core overclocking performance. I will also compare the performance of these two CPUs on both the original AR and the new A1 revision of to see if there happens to be any difference for Core 2 Duo overclocking.

In 2006, the disappointing limitations of Intelís NetBurst architecture gave AMD the chance it needed to take the lead in the CPU race but since its release, the impressive Core 2 Duo has again returned the performance crown to the halls of Intel. AMD has responded this month by drastically lowering the prices of their K8 chips in order to level the price/performance ratio playing field. This solution is really only intended as a short term tactic to hold on to market share until they release their upcoming 65nm processors, which they hope will bring them back into the performance race. Even now, with the price/performance ratio fairly even in the mid-range chips, AMD cannot currently match the overclocking prowess of the Core 2 processors, of which even the lowest end CPUs can easily reach 3GHz without breaking a sweat. Thatís enough to win the hearts of even the most under-dog-loving enthusiasts.

Released in the first quarter of 2007, the Core 2 Duo e4300 at 1.8GHz was the first and only installment in Intelís e4000 Allendale series until the slightly higher clocked e4400 at 2.0GHz became available this week. The e4300 is currently available for 208.45CAD from Direct Canada, but is expected to be further reduced within the coming weeks. (UPDATE: NOW $129!)

The e6400 is the second from the bottom of the original Conroe product ladder, just above the e6300. It will be eventually replaced by the new e6420 which, along with the e4400 and e6320, has also just entered retail channels this week. The e6420 and e6320 have all four MB of L2 cache enabled, and its advent has led to a price-drop for the e6300 and e6400. The key differences between the Allendale architecture-based e4300 and the Conroe architecture-based e6400 are:

  • The e6400 has a quad-pumped 1067 MHz FSB (front side bus) whereas the e4300 has an 800 MHz FSB, which mean that the e4300 is compatible with more chipsets but will be generally more limited in maximum overclocking potential. As the default FSB frequency is 200MHz and the multiplier is 9X, high overclocks can theoretically be reached without requiring a motherboard that is capable of high FSB speeds (a speed of 3.2 GHz is attainable with only a 355MHz FSB). Conversely, the e6400 has 8X multiplier and a 333 stock FSB so that a speed of 3.2 GHz requires a higher 400 MHz FSB (3200MHz ų 8X = 400MHz). The e4300 can also be overclocked using slower memory, although lower memory bandwidths can also be expected.
  • The e6000 series Conroes have a built in 4MB L2 cache, although the e6300 and e6400 have two of the 4MB disabled. The e4300 has only 2MB on the chip, and should run cooler as a result. The performance hit with the smaller L2 cache varies depending on the application, but is rarely more than five or six percent. The new e6320 and 6420 will have all 4MB L2 cache enabled.
  • Unlike the e6400, the e4300 has VT (virtualization technology) disabled but this does not result in a significant performance drop.

The e4300 (left) and the e6400 (right) show some distinctive architectural differences.

The Test Rig

Testing will be done using an EVGA 680i motherboard with the p26 BIOS, 2X1GB OCZ Gold pc6400 DDR2 RAM, an OCZ GameXStream 700W PSU, an EVGA 8800GTS 640 MB GPU overclocked to 600MHz GPU and 1000MHZ memory, a single 320GB Seagate Barracuda HD, in an Antec p180 Case. All testing was done in a room where the ambient temperature was held at 25C +/- 1C. The room is very small so the temperature was easy to control using baseboard heat and window when necessary.

E4300 vs. e6400 Stock Air Cooling and Settings

In this comparison, using the stock Intel heatsink, I measured performance of the two CPUs at stock settings using a series of benchmarks.

While the difference between the two CPUs at stock settings seems to be what we would expect, there is a performance scaling difference between the two that is less obvious. The stock speed of the e4300 is 85% of the stock speed of the e6400; however, the e4300 only performs at about 75% of the e6400ís performance in the benchmarks. This difference is probably mostly attributable to lower memory bandwidth with the e4300.

Air vs. Watercooling Comparison

For this review I have conducted an additional comparison between CPU performance under stock cooling, the Arctic Cooling Freezer Pro 7 air cooler, and a Customs water-cooling setup. The stock cooling that comes with the Core 2 Duos performd well compared to other stock cooling solutions offered in the past, and when paired with a Core 2 CPU, provides sufficient cooling to reach overclocks that were previously unheard of with stock cooling.

The Arctic Cooling Freezer Pro 7 is a no frills, inexpensive cooling solution that can be purchased for just under $25 CAD at Direct Canada, and is generally viewed as the best budget aftermarket cooling solution, and competes as well as many other more expensive heatsinks.

The stock intel cooler (left) and the Arctic Cooling Freezer Pro 7 (right)

Water cooling is another step above of any air cooling solution and can allow the overclocker to gain as much as 30% higher CPU speeds above air cooling. It can also extend the life of overclocked components by reducing the overall operating temperatures and slow down silicon migration. For an account on my first ever watercooling setup, and some what-to-dos and what-not-to-dos that I've learned Click Here.

The primary goal of this test was to find the difference in overclockability of the two CPUs using the different cooling solutions. Additionally, since both CPUs were capable of 3.2GHz with both the Arctic Cooling heatsink and watercooling, I wanted to see if watercooling would offer a performance advantage over air at 3.2GHz by allowing cooler operating temperatures.

Cooling Solution Comparison Results

The initial test compared both the e4300 to the e6400 at 3.2 GHz using the Arctic Cooling Freezer Pro 7 and the custom watercooling setup to see if the cooler operating temperatures afforded better performance. With air cooling, my sample e4300 was not able to reach 3.2 GHz at a 9X multiplier. With water, the maximum stable OC was 3.2 at 8X multiplier, so the FSB at this speed was 400MHz for both chips. As a result, there is no difference in memory bandwidth so that any performance difference would be a product of the different micro-architecture of the CPUs. However, as you can see in the graphs, there is almost identical performance for both CPUs at 3.2GHz under both types of cooling.

The aim of the second test was to determine the maximum stable overclock achievable using each cooling method: stock heatsink, the Arctic Cooling Freezer Pro 7 (ACFP7), and water.

I also found the maximum overclock for the original AR revision motherboard using the Arctic Cooling heatsink to see if there was any overclocking difference between it and the new A1 revision for Core 2 Duos.

An additional test was done to determine if a higher stable overclock was achievable using the e4300 in linked and synched memory mode vs. unlinked memory mode. This was only done for the e4300 as the memory used in the test rig was capable of the speeds required to run linked and synched with the e6400 which at 3.45 GHz would require the memory to operate at 863MHz.

The majority of benchmarks for this review were conducted using the p26 BIOS for the EVGA 680i, but in the last week, the p27 BIOS was released so I decided after the testing was completed to try it. Included in the graph are the overclocking results for both CPUs on watercooling with the p27 BIOS. It should be noted that for the purposes of this review, a setting was declared stable if all benchmarks were completed without lockup or crashing and two instances of Orthos stress test were run error free for a minimum of one hour.
The CPU voltages reported in this section are as entered into the bios, not as reported by the bios as 'actual'. The actual voltages were lower. For overclocking above stock settings, the FSB was set to 1.5V.

As you can see, the e6400 outperforms the e4300 for overclockability, and watercooling outperforms the aircooling. However, in terms of % overclock from stock, the e4300 achieves a 97% overclock (3.55GHz @1.63V- 394FSB), while the e6400 reached 81% over stock speeds (3.84GHz @1.64V- 480FSB). Both excellent results! If I were to calculate it in terms of dollar per GHz based on the current CPU prices, the e6400 is $69.00 CAD per GHZ, while the e4300 is only $58.87, so in this sense the real bargain is the e4300.

The maximum overclock reached for the e4300 at stock settings with the stock 9X multiplier was 2.81GHz (312MHz FSB). While not mind-blowing, this is 56% overclock and nothing to shake a stick at. However, it was not as high as I had hoped to achieve at stock voltage. As mentioned earlier, I more overclocking success with an 8X multiplier and at stock Voltage found that I could reach 3.0GHz (375MHz FSB). This is not far from the e6400's 3.15GHz on stock settings.

Somewhat surprisingly, the Arctic Cooling Freezer Pro 7 offered little advantage over the stock cooler, although it must be pointed out that despite setting the fan speeds to manual and 100% in the Bios, this heatsink fan would not exceed 1100 rpm even though it is capable of speeds over 2400rpm. I am not sure whether this was a problem with the fan or the motherboard, as I tried plugging it into the other fan connectors, but it still wouldnít spin quickly. I am sure that if it were working properly, I would have had slightly better overclocking success with it.

It is notable that I found no difference between the AR revision and the A1 revision overclocking maximums. I also ran benchmarks using the two CPUs at 3.2GHz on each revision but found no significant difference in performance between them. So rather than post another series of graphs to that effect, Iíll leave it at that.

Also interestingly, once I was able to break the 3.2GHz mark with the e4300 using the watercooling setup, I found that the 9X multiplier offered the highest overclock of 3.55GHz (394MHz FSB).

The biggest surprise in these results was the improvement offered by the new p27 Bios that I flashed to after running all of my initial tests. This Bios nicely cracked the 450Mhz FSB limit, allowing me to reach 480MHz with the e6400. I hadn't initially intended on reporting any results using p27 as it wasn't released until I was all but finished this review, but the effect it's had on my system had to be shared. Anecdotal reports indicate that many others with this board are also experiencing increased performance with the new Bios, but not everyone has seen gains.

Performance Comparison at Maximum Overclock

Now that weíve seen that the maximum stable frequency for the e6400 is about 8% higher than the e4300, letís see what that difference translates to in performance. I ran a series of benchmarks again with both CPUs at their maximum stable speed.

As you can see there is very little difference between the performance of the two CPUs even with the e6400 running at 300MHz higher frequency. While the overclock advantage of the e6400 is 8.2%, the actual performance advantage as measured by these scores is only 6%. This might give one pause when wondering if the nearly 30% higher price tag for the e6400 is worth it.

CPU Temperature Results

I recorded the idle and load temperatures of each CPU at stock settings and at their respective Maximum overclocks. The temperatures were fairly close between the stock cooler and the Arctic Cooling Freezer Pro 7, although these results might have been different if the latter's fan had been running at its full potential. With water cooling, the temperatures were significantly lower, even with much higher voltages at maximum overclocks. The difference between idle temperature and load temperature was also much closer than with the air solutions. It's important to consider that while the water vs. air OC temperature differences of 3-4 degrees may not seem like much, the volatge and clockspeed is much higher in the watercooled OC, so more heat is generated. As mentioned in my build log, I also made the mistake of using 11.2CFM fans on my radiator for this review, instead of the 38mm thick, 68.9CFM Panaflo fans which have dropped my idle temps by more than 5 degrees Celsius.

Table showing temperatures for each CPU under the three cooling types for stock settings and max overclock. The temperatures are presented as (idle, load) in Celsius. Load temperatures were defined as those reported by T.A.T. (Intel Thermal Analysis Tool) after one hour of Orthos stress testing.


The spirit of overclocking is alive and well and can be found in abundance in the plucky and affordable e4300. It compared well to the very capable e6400 that I have here, and while not matching it in overclocking, it wins out in dollars per GHz at both stock speeds and when overclocked. However, I canít stress enough that overclocking is like a lottery, with many variables in all components involved. Performance varies greatly between chips and batch numbers, so you can never be sure what youíll get.

Perhaps one of the greatest strengths of the e4300 aside from its price, is the higher multiplier which allows it to overclock without pushing the FSB and memory as high as Conroe CPUs. This can be a real advantage for the budget overclocker who would rather not buy a high-end motherboard and RAM. Unfortunately, I wasnít able to take full advantage of this 9X multiplier unless I was using watercooling and overclocked beyond 3.2 GHz, which is not the range that most e4300 users will be looking at. I do believe, however, that this is somewhat of an anomaly.

Stock cooling on these CPUs is also excellent, but with just a small investment in an aftermarket cooler like the Arctic Cooling Freezer Pro 7 you can squeeze some extra performance out of that CPU. I had some trouble with fan speeds on my cooler, but these are generally hailed as excellent performers for the money and in practice should generally earn their keep in the form of increased clock speeds, lower temperatures, and silent operation.

Water cooling of course, offered the lowest temperatures and the greatest leap in overclocking. I can not honestly say that the performance advantage justifies the much greater expense of water cooling, but for many enthusiasts, it is a must.

While these two processors are a great bargain now, they will be dropping further in price in the very near future, so keep your eyes on Direct Canada for pricing. (UPDATE: NOW $129!)

The Core 2 Duo e4300 has earned my recommendation!

FYI, the batch number of the e4300 used here is Q644A419 and the e6400 is L631A571.

I would like to extend a special thank you to Direct Canada for providing the e4300 for review!

Please feel free to discuss this review in the forum!