Tuesday, June 6, 2006

Turn Your nForce 570 into nForce 570 SLI. Successful First Experiments

5:46 pm | Aleksey Razin

Our regular readers may remember that by closing the bridges on the chipset North Bridge we could make nForce4 chipset support SLI and SATA-300 turning it into an analog to more expensive solutions. Keeping in mind that the new nForce 5xx series of chipsets are single-chip solutions based on nForce 570 SLI chip, the idea of modifying it is also very tempting.

The first experiments of the kind have been performed by our colleagues from HKE_PC site. They may have never decided to undertake transformations like that if it hadn’t been for the Magic-Pro A2N5 mainboard on nForce 550 chipset that supported the SLI mode despite the nominal features of the chipset. The further investigation followed the already familiar algorithm. The thing is that the origin of nForce 5xx chipsets allows the mainboard makers to retain the PCB design when they shift from one mainboard model to another. All excessive functions are simply blocked on the hardware level. If we compare two mainboards with the same design but based on different chipsets, we can find these differences and then unlock the necessary features.

Of course, first of all we took a closer look at the chipset and the bridges on its packaging. The difference between nForce 550/570 and nForce 570 SLI and nForce 590 SLI was evident: chipsets with SLI support had no resistor in the position marked with red circle:

However, removing this resistor didn’t let you use the second PCI Express x16 slot, because it simply wouldn’t let the second graphics card work in PCI Express x8 mode. They had to look for other differences in the mainboard design. By comparing two MSI mainboards our colleagues managed to find those differences: they discovered two groups of elements around the chipset North Bridge and the second slot. They are marked with red on the pictures below:

It was even more complicated because the nForce 570 based mainboard didn’t have all these switches, so the guys had to remove those elements from the “donor”-mainboard based on nForce 570 SLI chipset onto the mainboard that didn’t have them. Of course, this modification technique is hardly suitable for mass home experiments.

When the resistors have been moved over, the system thought that it was dealing with nForce 590 SLI chipset, which automatically changed the second PCI Express 1x slot to PCI Express x8.

Now, even the driver thought that it was an nForce 590 SLI based mainboard, so SLI mode was enabled:

The modified mainboard demonstrated the same performance level as its fellow board based on a real nForce 570 SLI. Theoretically, this transformation allows saving about 50% of the mainboard cost. The only problem is that this modification is extremely complicated and may be dangerous for the board. Secondly, there are not so many mainboards on nForce 550 and nForce 570 chipsets that will boast two PCI Express x16 slots. Although they will probably be able to accommodate GeForce 7950 GX2 graphics card that implements SLI principles by using only one single PCI Express x16 slot and a chipset supporting SLI technology.

Sempron 3600+ Overclocking. Budget Solution for Overclocking Fans?

5:35 pm | Ilya Gavrichenkov

3600+ model is the today’s top Sempron processor in Socket AM2 form-factor. It works at 2.0GHz, features 256MB L2 cache and supports dual-channel DDR2-667 memory. The majority of the potential AMD platform fans are certainly curious to know what this CPU is capable of during overclocking. The reports from XtremeSystems.org forums give us a great chance to take a first look at successful overclocking of a Sempron 3600+ processor.

First of all, we would like to point out that a lot of Socket AM2 mainboards allow DDR2-800 support for single-core processors. All you need to do to enable it is set a proper divider. For example, Sempron 3600+ with 2.0GHz nominal clock speed requires 1/5 divider. For DDR2-667 mode it will use 1/6 divider and for DDR2-533 mode it will support a less convenient 1/8 divider, that will nevertheless support only DDR2-500 mode. Each Socket AM2 CPU has “inconvenient” dividers like that.

When the Vcore is raised to 1.45V, Sempron 3600+ processor reached 2.87GHz frequency with a default Athlon 64 3000+ cooler for Socket 939. This is actually a great example of how you could use boxed Socket 939 coolers with the new Socket AM2 processors.

I cannot claim that this Sempron 3600+ overclocking result is remarkable for all Socket AM2 CPUs, but it is a very good achievement for a budget solution. The youngest Sempron models may feature even lower overclocking potential, since AMD has already learned to sort out cores according to their frequency potential, so there are considerably less overclocking wonders among the low-end models. Anyway, if you are looking into getting a Socket AM2 system, then Sempron may be a pretty decent choice to begin with.

What Conroe Model Suits Best for Overclocking? Frequency Potential of the Eldest and Youngest Processor Models

5:31 pm | Aleksey Razin

Hardware enthusiasts now have only the very first Conroe samples at their disposal, however this doesn’t stop them from researching their overclocking potential with great excitement. Not so long ago we reported about a successful overclocking attempt when the Core 2 Extreme X6800 (2.93GHz) processor with unlocked clock frequency multiplier was pushed to 5.0GHz with the help of liquid nitrogen. Of course, not all overclockers will be able to hit these heights. Firstly, far not every overclocking fan uses liquid nitrogen cooling. Secondly, the actual Core 2 Duo E6xxx processors with the limited clock frequency multiplier can very rapidly exhaust the potential of the mainboard to raise the system bus frequency. Unlimited clock frequency multiplier will only be available on Core 2 Extreme X6800 (2.93GHz) processors that will sell for at least $999.

Let’s take a closer look at the new record-breaking Conroe overclocking results that are still very illustrative. For example, this discussion on XtremeSystems.org forums led by Coolaler guy tells about successful overclocking of Core 2 Duo E6700 (2.67GHz) with B0 core stepping. He managed to reach 3.9GHz with the Tuniq Tower 120 air-cooler.

To achieve these results he had to voltmod the MSI 975X Platinum mainboard revision 2.0B, so that it allowed to increase the Vcore to 1.78V. In fact, the CPU also worked at 4.0GHz, however, the benchmarks couldn’t be completed at this speed without losing the system stability. Anyway, we assume that it shows clearly that the top models of mass production Conroe CPUs will be able to overclock to 4.0GHz with air-cooling.

I would like to specifically stress the words “top models”. Take a look at the screenshot: with 10x clock multiplier the system bus frequency equals 390MHz. it is a pretty high value and the slower is the processor model, the higher this frequency should be to reach the maximum core potential. Core 2 Duo E6700 (2.67GHz) will cost around $350. Remember this number, as it is important for our today’s discussion.

XtremeSystems.org forums have described the first overclocking experiment with the Conroe CPU featuring 2MB L2 cache. All the previous Core 2 Duo E6xxx samples discussed featured 4MB L2 cache even if the mass production modification were to have only 2MB. Now the famous FUGGER managed to get his hands on a Core 2 Duo E6300 (1.86GHz) CPU with B0 core stepping that features only 2MB L2 cache. The CPU, however, is a dual-core one, even though we have always believed that Allendale code name on the screenshot stands for the single-core model. Looks like the so-called Conroe-L processors will be codenamed differently.

The experiment showed that even if the second core was disabled completely and the Vcore was set to its maximum, Core 2 Duo E6300 processor doesn’t allow to increase the system bus frequency beyond 477MHz. with the maximum clock frequency multiplier of 7x, it can only clock to 3.33GHz. It is not a bad result, but the mainboard should features really good overclocking-friendly options to achieve this. Most mainboards may face serious difficulties during this overclocking attempt, especially if the implemented Conroe support didn’t imply wide frequency range for the system bus.

FUGGER stopped at 3.22GHz frequency achieved with a serial Freon cooling system. With the processor Vcore at its nominal value, the CPU clocked to 2.33GHz. By raising the Vcore to 1.4V, he gained about 700MHz extra. These results, indicate once again that low clock frequency multiplier will become a limiting factor for successful overclocking of young Conroe models. The minimal multiplier is 6x, which is set by the EIST technology supported in all Core 2 Duo E6xxx. By the way, Core 2 Duo E6300 (1.86GHz) will be the youngest Conroe model launched this year. The dual-core Core 2 Duo E4200 (1.6GHz) with 800MHz bus is due in early 2007. Actually, despite the lower price, it will support higher clock frequency multiplier of 8x and lower nominal system bus frequency of 200MHz, which will make it a more attractive solution for overclockers.

Core 2 Duo E6300 (1.86GHz) will cost $183, which is almost 3 times less than the price of Core 2 Duo E6700 (2.67GHz). However, low clock frequency multiplier will shift all the load to the mainboard, which may prevent you from squeezing all the juices out of the CPU. If you intend to hit certain frequency, then it makes more sense for you to spend more money on a model from the middle of the product line-up, instead of getting the slowest one. In fact, P965 based mainboards may save you some trouble, but they will not be cheap, also. So, efficient Conroe overclocking will require some tangible financial investments.

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