by Ilya Gavrichenkov
10/16/2006 | 12:27 PM
This article continues the series of reviews devoted to choosing the right overclocking friendly memory kit for systems built around the promising Intel Core 2 Duo processors. In our previous articles we have already discussed in detail fast and expensive PC2-8000 memory (for details see our article called DDR2 SDRAM to Hit 1.1GHz: Corsair Dominator vs. OCZ PC2-8800 Gold Edition) as well as even faster one (for details see our article called Choosing the Right Memory for Core 2 Duo Platform - Part 2: DDR2-1000, DDR2-1067 SDRAM). Today we feel it is time to pay due attention to less supreme but still very interesting DDR2-800 SDRAM.
First of all I would like to stress that in most cases you should consider DDR2-800 SDRAM to be the best choice for Core 2 Duo based platforms. As we have already demonstrated in this article, the overclocked system can reach its highest performance level in case the processor bus and the memory bus are clocked synchronously. And keeping in mind that the typical Conroe overclocking usually occurs at about 400MHz FSB frequency, then the overclocker’s DDR2-800 SDRAM can be recommended as the best choice for most enthusiasts. Especially, since most PC2-6400 memory modules have proven capable not only to work at 800MHz with pretty aggressive timing settings, but also to be overclocked to hit much higher speeds at slightly longer latencies.
Of course, we shouldn’t disregard the efficiency of fast memory modules for overclocker systems, especially after we have described their universality in our previous materials. As our tests revealed, faster overclocker memory modules designed to run at 1GHz+ frequency can work at 800MHz with pretty aggressive timings. However, the price point is yet another important factor that cannot be omitted here. PC2-6400 SDRAM modules are much more affordable than 1GHz or faster memory solutions. Therefore, these memory modules enjoy most popularity among overclockers.
I have to say that high efficiency of synchronous clocking of the processor and memory busses is not the only argument in favor of mainstream overclocker’s memory solutions. Our tests showed that far not all LGA775 mainboards compatible with Core 2 Duo processors can ensure stable functioning of the memory at 1GHz or higher speeds. For example some i975X based mainboards, namely the popular overclocker’s product -ASUS P5W DH Deluxe, experience certain problems. As a result, PC2-8000 and faster memory can only be really used to the advantage in Intel P965 based platforms, which limits the application field for this memory quite noticeably.
By the way, this is one of the reasons why we selected ASUS P5B Deluxe mainboard as a test platform for our DDR2 SDRAM test for Core 2 Duo, because this newer Intel chipset is better optimized for work with the high-speed DDR2 SDRAM. At the same time I would like to point out that DDR2 memory usually overclocks even better in Socket AM2 systems. However, for the reasons mentioned in the previous articles of the series, today we are going to look at DDR2 SDRAM performance and operation only in systems with Core 2 Duo processor.
At this point I would only like to add that the memory controller of the new Intel P965 chipset boasts a few features distinguishing it from the predecessors and competitors. The engineers did their best to make this memory controller as intellectual as possible: for the first time it features out-of-order commands execution algorithms that allow more efficient use of open memory pages. As a result, it helps to utilize the DDR2 SDRAM memory bus gets more effectively and reduce the latencies during data processing. So, the iP965 memory controller boasts very different features unlike similar units built into other processors and chips.
However, let’s not veer too far away from the main goal of our today’s test session. As we have already mentioned we will be looking at 2GB PC2-6400 SDRAM overclocker’s memory kits. All the tests will be conducted in the following test platform:
We used our standard set of benchmarking tools for memory stability testing: Memtest86, S&M and prime95. The memory performance was analyzed at the modules nominal voltage as set by the DDR2 SDRAM manufacturer.
Corsair Company is a constant participant of all test sessions devoted to overclocker’s memory on our site. And this is not surprising at all, actually, as the product range offered by this manufacturer is quite extensive not only from the feature prospective, but also from the price point. I have to say that Corsair offers the enthusiasts two kits with the memory capacity of 2GB and working frequency of 800MHz. They are TWIN2X2048-6400С3 and TWIN2X2048-6400С4. The former is a more expensive solution supporting 3-4-3-9 timings, while the latter one uses 4-4-4-12 timing settings. We got a more affordable solution for our today’s tests: the kit with less aggressive timings and broader availability in retail these days.
Corsair TWIN2X2048-6400С4 memory kit consists of two identical DIMMs, each 1GB big and each with its own part number – CM2X1024-6400C4. According to the manufacturer, these modules work at the nominal frequency of 800MHz, timings set at 4-4-4-12, 2T Command rate and 2.1V voltage.
I would like to point out right away that Corsair TWIN2X2048-6400С4 kit can be regarded as a close relative of the recently reviewed Corsair TWIN2X2048-8500С5 kit (for details see our article called Choosing the Right Memory for Core 2 Duo Platform - Part 2: DDR2-1000, DDR2-1067 SDRAM). And it is not only about the exterior design similarity. Of course, they look similar. Like many other Corsair overclocker’s kits, both sides of the TWIN2X2048-6400С4 DIMMs are covered with traditional black-anodized aluminum heat-spreaders. There are stickers with the manufacturer’s logo and product specifications on top of each heat-spreader. However, the major similarity between Corsair TWIN2X2048-6400С4 and the recently reviewed other Corsair solution is hidden right beneath these heat-spreaders: both these modules are built using the same Micron chips. And the difference between the Corsair TWIN2X2048-6400С4 and the faster modification is determined mostly by the voltage, which equals 2.1V in our case and 2.2V in case of memory modules designed to work at 1066MHz frequency.
The stickers on the heat-spreaders of the memory modules contain the information about the part number, memory capacity, nominal frequency and timings. I would like to draw your attention to the fact that we have memory modules of revision 1.2, which has also been indicated on the stickers. The distinguishing feature of this modification is that it has been certified to work in SLI systems, i.e. they support EPP (Enhanced Performance Profile) technology from Nvidia.
You can see all this in the modules’ SPD:
To ensure that these memory modules are compatible with different mainboards, there are two work modes listed in the standard PSD field: with 4-4-4-13 timings and 533MHz frequency and 5-5-5-18 timings and 800MHz frequency. However, these numbers do not actually reflect the real capabilities of the Corsair TWIN2X2048-6400С4 memory kit. The manufacturer suggests that you should check out the potential of this solution in the EPP section. This section serves to automatically set up the memory subsystem of platforms built around any Nvidia nForce 500 chipsets based mainboards. This is where we come across the DDR2-800 mode with 4-4-4-12 timing settings that should work at 2.0V Vdimm, according to EPP. Moreover, Corsair engineers have also declared in EPP for Corsair TWIN2X2048-6400С4 modules the 1066MHz frequency with 5-5-5-15 timings and 2.2V voltage. In other words, the PC2-6400 memory modules from Corsair we are reviewing today turned out similar to Corsair TWIN2X2048-8500С5 not only on the component level: even the manufacturer stresses that they are identical, as you can see clearly in the SPD/EPP of these modules.
Very intriguing situation. So far we have got a few very clear indications that Corsair TWIN2X2048-6400С4 and Corsair TWIN2X2048-8500С5 should be exactly the same. It is really interesting to see whether our practical testing will confirm this statement, especially since the today’s memory kit is more than $100 cheaper than the TWIN2X2048-8500С5. The graph below shows the maximum frequencies when the tested memory remained stable.
Although we are no kids anymore, Corsair once again makes us believe in wonders. Corsair TWIN2X2048-6400С4 really turned out very close in performance to the more expensive memory. Although it is running not completely neck and neck, the performance difference can be explained by lower nominal voltage of the PC2-6400 modules. In other words, Corsair TWIN2X2048-6400С4 is an excellent memory kit that can easily perform the role of PC2-8500 SDRAM. With the timings set to 5-5-5-15 it hits far beyond 1067MHz. As for the nominal latency settings, Corsair TWIN2X2048-6400С4 works stably and reliably at up to 950MHz frequencies.
Another testing participant of our today’s DDR2 race is Crucial Company with their Ballistix memory kit. I would like to make it clear right from the beginning that since Crucial is Micron’s daughter venture, Crucial Ballistix DDR2 overclocker’s memory is very popular among computer enthusiasts. Of course, since it is the memory modules built with Micron chips that beat all overclocking records these days.
Crucial Ballistix BL2KIT12864AA804 memory kit we received contains two 1GB memory DIMMs shipped in a very sturdy and original carton box. The default work mode for these modules is the same as by many of the competitor solutions. They are designed to work at 800MHz with the timings set to 4-4-4-12 at 2T Command Rate. The manufacturer’s recommended voltage setting has been raised to 2.2V.
The modules included into Crucial Ballistix PC2-8000 kit are based on original black PCB and equipped with standard stamped yellow-anodized aluminum heat-spreaders fastened with two metal clips. The URL of the company web-site crucial.com and the Ballistix series name are painted in black on top of the heat-spreaders. There are no details anywhere on the modules, only a small sticker with the part number that can be used to search for the detailed product info on the company site.
The information recorded in the SPD of Crucial Ballistix BL2KIT12864AA804 looks very scarce:
Here you can only find the info on the default work mode for these modules declared by the specs. Unfortunately, it may cause some compatibility problems when the system is started for the first time, because the work mode set in the SPD requires the Vdimm to be raised above the nominal 1.8V for DDR2. In other words, in some cases the default memory settings may not be operational unless you manually increase Vdimm.
Crucial Ballistix BL2KIT12864AA804 demonstrated very remarkable results in our tests:
First of all I would like to point out that this is the only memory kit in our today’s testing that worked fine at the most aggressive timings of 3-2-2-8. However, with all other timing settings it lost to the above described competitor from Corsair. However, I have to say that at 4-4-4-12 timings it ensured stable operation of the system at frequencies very close to 900MHz. Although Crucial Ballistix BL2KIT12864AA804 failed to perform as PC2-8500: with the least aggressive timing settings possible and the highest Vdimm it has hardly got over the 1GHz bar.
For our tests of DDR2-800 memory modules GeIL Company offered us one of their top products – a 2GB memory kit named GeIL GX22GB6400UDC. The color of the heat-spreaders covering the memory chips indicates that this memory belongs to high-speed enthusiasts’ line-up. While the mainstream GeIL memory solutions come equipped with non-colored aluminum heat-spreaders, the elite products targeted for hardware enthusiasts stand out thanks to bright red color.
GX22GB6400UDC memory modules belong to this particular “red” series. Like all other similar solutions, they are intended to work at 800MHz with 4-4-4-12 timing settings. As for the Vdimm, GeIL declares pretty wide supported range: from 1.8 to 2.3V.
Looks like color of the heat-spreaders is the only distinctive exterior difference between this solution and the other GeIL products. The heat-spreaders are of standard design with embossed logo and a marking sticker that contains the product part number, working frequency and timings.
I believe that GeIL GX22GB6400UDC memory modules are a very unusual solution, and not only because of the fact that the manufacturer provided no recommendations regarding the DIMM voltage. It is even more strange that the chips used for these memory modules are unmarked, so we cannot actually define their origin. However, the benchmark results indicate very clearly that these are not Micron chips.
Even the SPD report looks a little strange:
The modules name written in the SPD is not connected with their part number in any way, and suggests very clearly that their memory timings should be not 4-4-4-12 but 5-5-5-15. I have no idea where this is coming from. As far as the rest of the SPD data is concerned, it is optimized to ensure compatibility with most mainboards out there.
The practical performance of GeIL GX22GB6400UDC memory modules wasn’t too impressive although we ran all tests at 2.1V Vdimm.
However, I have to admit that GeIL GX22GB6400UDC managed to hit pretty much the same frequencies as the competitors at its default timings of 4-4-4-12. Although, these memory modules are not universal. Further increase of the latencies and (or) Vdimm didn’t result in any increase of the modules’ overclocking potential.
G.Skill Company, the Taiwanese manufacturer of overclocker’s memory modules, cannot boast being as popular as the grands of the market like OCZ and Corsair. However, they are working really hard on winning the users’ hearts, and one of the things they are doing – participating in numerous test sessions and comparisons.
Today we would like to introduce to you G.Skill F2-6400PHU2-2GBHZ DDR2-800 SDRAM kit that includes two memory DIMMs, 1GB each. According to the official specification, this memory should work with 4-4-4-12 timings and 2.0V-2.1V Vdimm.
The exterior design of G.Skill memory modules is pretty common. They are covered with standard black-anodized aluminum heat-spreaders with a company logo and identification sticker on top of them. This sticker reports the product part number, memory capacity of the DIMM, default latency settings and recommended voltage.
The SPD of G.Skill F2-6400PHU2-2GBHZ memory modules contains pretty standard set of data:
As we see, the manufacturer declared two work modes to ensure maximum compatibility of their solution. These modes are: DDR20533 with 4-4-4-13 timings, and DDR2-800 with 5-5-5-18 timings.
The chips used in G.Skill F2-6400PHU2-2GBHZ are made by Elpida. This certainly has its influence on the test results we obtained. First of all, you should keep in mind that you have to push the Write Recovery Time and Row Refresh Cycle Time timings to the limit if you want to get the memory modules built on these chips to work at their maximum frequencies. Luckily, these particular timings do not affect the performance that much.
I have to say that I was slightly disappointed with the maximum working frequencies, when G.Skill F2-6400PHU2-2GBHZ memory modules remained stable. Against the background of the results obtained from Micron based DIMM modules, they are somewhat low (all the tests were run at 2.1V Vdimm).
G.Skill F2-6400PHU2-2GBHZ modules run slower than the competitors based on Micron chips with 3-3-3-10 timings as well as with 4-4-4-12 timings. It makes no sense to set the timings to even less aggressive values, because in this case the frequency potential of the modules will get worse. And even raising the voltage significantly will not help in this case.
Kingston Company, that deserves being called one of the oldest and more respected memory manufacturers in the industry, offered us their KHX6400D2LLK2/2G modules kit with the total capacity of 2GB. This kit belongs to HyperX product line that has been specifically designed for overclocker’s systems. Like all other today’s testing participants, this DDR2 SDRAM is designed to work at 800MHz with 4-4-4-12 timings. The default voltage for this kit is declared as 2.0V.
I would like to stress that Kingston HyperX KHX6400D2LLK2/2G memory modules can be called the most beautiful ones in our today’s test session. Although they use standard stamped aluminum heat-spreaders for cooling, the blue color of the heat-spreaders goes very stylishly with the read-and-white Kingston HyperX and DDR2 logos. The stickers on the heat-spreaders tell you the product part number, some not very exciting technological details and the default Vdimm, which is marked as 1.95V for some reason.
Note that unlike other memory makers, Kingston also placed the kit marking on the package. The corresponding sticker is much more informative than the stickers on the modules themselves. Besides the part number, the package sticker also contains the frequency and CAS Latency settings of the DIMMs in the kit.
SPD of these modules reports quite common data, which is different from the modules spec, but ensures compatibility with a great number of mainboards.
As for the internal structure of Kingston HyperX KHX6400D2LLK2/2G modules, it is less impressive than the exterior. Unfortunately, the manufacturer didn’t take the best memory chips for this solution. Kingston HyperX KHX6400D2LLK2/2G modules are built using Elpida chips, so they cannot boast great overclocking potential.
This, when the timings are set to 3-3-3-10, Kingston HyperX KHX6400D2LLK2/2G kit cannot work even at 600MHz. By setting the timings to their defaults of 4-4-4-12, we can hit the frequencies approaching the declared values, which still looks not very remarkable against the background of the competitors we have already tested. If we raise the timings to 5-5-5-15, the situation will hardly change dramatically. Although the memory modules can work at frequencies close to 1GHz, the overall result is much lower than the solutions using Micron chips can achieve.
Mushkin Company has also decided to participate in our extensive DDR2-800 testing this time and offered us their 996523 memory kit. Mushkin is a very well-known manufacturer of overclocking-friendly memory solutions with a long history and we will do our best to get more products from them reviewed on our site in the future. This company was founded in 1994. It is a daughter venture of the Ramtron International Corporation, which name is appearing on the New more and more often in relation to ferroelectric memory (FRAM).
Mushkin 996523 XP2-6400 DDR2 kit includes two DDR2 SDRAM DIMMs of 1GB each. This memory is designed to work at 800MHz with 4-4-3-10 timing settings and Vdimm between 1.9V and 2.1V. Here I would like to point out right away that, these memory modules have the most aggressive timings settings in the official specs than any other testing participants of our today’s roundup. And it seems to be not the common trick most manufacturers use these days, namely the increase in the memory voltage.
One of the greatest distinguishing features of Mushkin 996523 XP2-6400 DDR2 memory modules is their brand-name heat-spreader design known as FrostByte. Although I have to say that at a closer look it is none other but two stamped aluminum plates fastened to the chips with metal clips. Their only unique peculiarity is slightly unusual configuration that can hardly ensure much more efficient heat dissipation procedure than any of the competitors’ heat-spreaders.
There is a color manufacturer logo and a sticker with some DIMM specs on the black heat-spreader surface. The sticker contains the part numbers of the modules, their default frequencies and timing settings.
So, the differences between the nominal specifications of Mushkin 996523 XP2-6400 DDR2 modules and their competitors should probably be explained by the special chip selection at production stage. By the way, these memory modules are built using excellent Micron chips, the same as the ones used in the best Corsair and Crucial products.
The SPD of Mushkin 996523 XP2-6400 DDR2 memory DIMMs is quite standard for overclocking-friendly products:
It stores information about the memory work modes at 667MHz and 800MHz frequencies that are required for proper compatibility.
Mushkin 996523 XP2-6400 DDR2 proved very efficient during our test session. They remained fully stable all the way through and ran at just a tiny bit below 1GHz speed. They looked great even against the background of their rivals built with the same Micron chips, not to mention the solutions using slower Elpida chips. The chart below demonstrates the actual results obtained at 2.1V Vdimm.
With the timings set at 4-4-4-12, Mushkin 996523 XP2-6400 DDR2 worked stable at almost 1GHz frequency. However, when we reset the timings to 5-5-5-15, Mushkin memory went well beyond 1.1GHz speed. As a result, we can place this 2GB memory kit among the best DDR2-800 SDRAM kits out there these days.
In our few recent articles devoted to the best memory choices for Conroe platform we have been trying to convince our readers that any overclocker system should do just great with DDR2-800 SDRAM, and the faster memory may be of interest only to a limited number of extreme overclockers. Now that we have just finished one more test session, our arguments in favor of this statement have become even more meaningful. The thing is that the properly selected overclocking-friendly PC2-6400 SDRAM hardly yields to faster PC2-8000 SDRAM in terms of its frequency potential. Well-made DDR2-800 that is designed to work at 4-4-4-12 timings can perform as DDR2-1000 or even DDR2-1067 SDRAM with less aggressive timing settings. However, by getting PC2-6400 memory modules that are slower according to their official specifications, you can win big financially. The memory module kits that we have reviewed today are definitely cheaper than the kits with the same 2GB capacity but specified to work at post-1GHz speeds by default.
So, before choosing the right DDR2 SDRAM for the system every overclocker needs to make sure that he/she understands correctly what DDR2-800 SDRAM memory is the best. The results of our numerous tests revealed the following empirical rule: the memory modules built using Micron chips overclock the best. So, we would certainly recommend the solutions like that.
As for more specific advice from us, we can say that Corsair TWIN2X2048-6400С4 and Mushkin 996523 XP2-6400 DDR2 should definitely become your primary choice. These two kits work stably at default speeds and timing settings and at the same time offer significant overclocking potential, so that they can easily compete with PC2-8000 SDRAM.