Experiences with the Core 2 Duo E6300
Moving to a new platform is never easy. In most cases, it will involve a completely new install of all software, new drivers plus coping and handling a number of quirks and odd behaviors. Even with a chipset from a leading manufacturer such as Intel, our experience with Core 2 Duo and Intel P965 chipset have not been all bells and whistles. Granted, most, if not some of the problem we face can be blamed on different manufacturers implementations.That does not mean moving to a Core 2 Duo platform do not offer any advantages. To the contrary. Performance wise, Core 2 Duo have proven itself to be a much stronger performer than AMD's current offering, more so when performance per watt is factored into the equation. Add a competitive price to the mix and it's only natural gamers and hardware enthusiast quickly moved in droves to Core 2 Duo platforms. However, for some of us, the icing on the cake is definitely the overclocking potential of these Core 2 Duo processors. It wouldn't be too much of a stretch to say Intel have returned to its Pentium II / Celeron days.
Who could forget Intel's famous Celeron 300A processor? First marketed as a low-end, cut down version of Intel's Pentium II processor, it quickly became the staple of overclockers everywhere due to its overclocking potential and easiness to overclock. You can raise the FSB (Front Side Bus) to 100 MHz, sometimes without changing the processor's voltage. At that speed, you'll get a very affordable platform offering the performance of a Pentium II 450 MHz at a fraction of the cost. Intel hadn't even bother disabling multiprocessing capabilities of the processor. With ABIT's famed BP6, one could built a low cost, dual processor setup with two Celeron 300A, either for a workstation, server or just fooling around with dual processor systems. The introduction of the 133 MHz FSB only propel the performance of these processors even more. VIA's 694x chipsets were particularly interesting, allowing users to raise the FSB up to or near 133 MHz then maximize bandwidth by having the memory clocked at 166 MHz. For some, it became a much more viable alternative than Intel's ill fated 820 chipset with Rambus and ALi 's Magik chipset with DDR-SDRAM.
Out of the number of processors available, the Core 2 Duo E6300 and the recently launched E4300 are probably the most sought after for its overclocking potential and price. Unfortunately, we were unable to get our hands on the E4300 just yet, but we've been toying with our E6300 processor for some time now. Today we're going to share what we found.
Setting Up
Before moving on to the technical stuff, first we'd like to discuss the reasons - why overclock your processor or any other component for that matter? Well, everything else being the same, running at a higher clock means the processor can do more cycles at one time and more cycles means more data gets crunched, which of course translates to higher performance. However please keep in mind that overclocking means you're running above the manufacturers specification, thus damages that might and very likely occur if you're not careful and take necessary precautions are not covered by the manufacturers' warranty.So much for the disclaimer, now on to the other stuff.
Besides the obvious performance benefits (and the sheer fun and sometimes frustration) with any overclocking endeavor, with this article we wanted to see what are the various performance influencing factors in a Core 2 Duo setup. Running at high clocks alone do not guarantee high performance - we also need to make sure the processor gets enough data to be processed. Since this is usually the case, we are especially interested in learning the impacts of the FSB, synchronous / asynchronous FSB and memory settings and DDR2-SDRAM timings on performance. All these factors contribute greatly to achieving optimal performance from your processor.
Our test setup
Intel Core 2 Duo E6300 socket LGA-775
2 x 512 MB A-DATA Vitesta 5-5-5-18 PC6400 DDR2-SDRAM
2 x 1024 MB Kingston KHX 5-5-5-16 (at PC6400) PC8500 DDR2-SDRAM
Gigabyte Radeon X1950 Pro 256 MB graphics card
Gigabyte P965-DS3P Intel P965 motherboard
Maxtor DiamondMaxPlus9 80 GBs Serial ATA 8 MB buffer
LiteOn 1673S DVD-RW
Tagan TG530-U15 530 watts ATX/BTX power supply
Settings:
Core: 1.225 volt
DDR: 1.9 volt (default motherboard voltage)
PCI-E clock: 100 MHz
Memory Timings: SPD except otherwise specified
FSB, Multipliers and Voltage Settings
Unlike previous processors, there are two tools we can use to push Core 2 Duo processors to the limit. The first is of course the FSB or Front Side Bus. Both Intel's P975 and P965 chipsets offer the possibility of using much higher FSBs than the official specified 266 MHz (1066 MHz effective) on Core 2 Duo Processors. There are at least three major FSB of choice if you want to run synchronously with various DDR2-SDRAM standards: 333 (for DDR2-667), 400 (DDR2-800) and 533 MHz (DDR2-1066). Most motherboards offer the option to raise the FSB in 1 MHz increments, so you have a very wide selection of FSBs to choose from. The second tool is something that have been missing for quite some time from Intel's processor - multiplier control. At last, Intel have chosen to follow AMD's footsteps by allowing downward multiplier control on Core 2 Duo processors. This allows us to experiment with much higher FSBs than before. For example, instead of topping off at 7 x 343 MHz to achieve a processor clock of 2.4 GHz, we can also use 6 x 400 MHz. Traditionally, only Engineering Samples - ES - versions of Pentium III and 4 processors allow multiplier changes.Of course, these are not the only requisite for getting a high, stable overclock. Voltage control is just as important. Thankfully, the performance per watt oriented design and Intel's excellent fabrication process have allowed Core 2 Duo processors to run at very low voltages and much, much lower temperatures than Pentium 4 processors. It's not strange to find Core 2 Duo processors running just fine at much lower voltages than officially specified. Take the Core 2 Duo E6300 - our sample runs smoothly at 1.1 volts (1.866 MHz) although the official specification clearly states 1.35 volts for normal operation. Low voltages usually mean not only do we have much more overclocking headroom, but also much lower thermal dissipation. In layman's terms, that means less heat and thus less hassle in cooling down the processor. Throughout the whole process of testing for this article, we found the stock cooler does quite an adequate job of cooling a 2.8 GHz Core 2 Duo E6300 at 1.225 volts (though temperatures did get a little too high for our taste at full load for prolonged periods). You probably notice the shot below shows 1.2 volts - that's no mistake. This is confirmed by both SpeedFan and Gigabyte's own V-Tuner. It would seem the Gigabyte P965-DS3P have a 0.025 volts deficit hence the difference.
Some might ask, why thermal dissipation and temperatures are so important, both in general use and overclocking setups? Well for one, lower temperatures mean longer lifespan. They can also help us avoid thermal protection features from kicking in, which is something of a nuisance if you want to get the most performance out of your processor. Intel first introduced their processor thermal management technology with Pentium 4 'Willamette' processors. Should the processor reach a certain temperature that's deemed unsafe by the engineers at Intel, it will automatically scale down the clock and run slower to keep its temperature from getting any higher. It's quite effective in minimizing risk from thermal damage or in simpler terms, burning itself up. Tom's Hardware once documented this feature, quite dramatically we might add.
Now, back to the FSB or Front Side Bus. It is generally accepted that the higher the FSB you use, the higher the performance you'll get. That's because assuming timing and latency are constant, you effectively pushing more data from and to the component you're overclocking. Even if the processor can't process all the data, you will still experience some gains because 'real' latency - idle cycles - are lower with higher FSBs because the take up less time. However, some more adventurous overclockers have actually reported lower performance at higher FSBs with Core 2 Duo processors. Of course, we're curious to see if this is true and if there is a point of diminishing return, at what clock and is there something we can do about it.
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