EVGA X58 SLI LGA 1366 Motherboard Review

Stability & Overclocking Results

A new chipset, new processors, on-die memory controllers, and new architecture equates to an entire new way in which everything functions. This means that overclocking the i7 isn't quite going to be like the Intel processors of old. The FSB is gone and replaced with a new Base Clock (BCLK) which every other frequency runs off of through multipliers. Initial thoughts were that with the FSB gone, the overclocking capabilities would be unlimited and unlocked multipliers would be a thing of the past...not quite. You see, Intel has still managed to handi-cap their lower end processors by imposing an inherent limitation on BCLKs.

The lowest QPI Bus multiplier is 18X, which runs the QPI Bus at around 4GHz with a BCLK of 220. This is about the limit that any QPI Bus is going to be able to handle at this point in time, thus limiting BCLK to 220 or lower and in essence, leaving us overclockers in the exact same situation. Processor overclocks are going to be limited by the BCLK instead of the FSB. Lower end model CPUs like the i7 920 and i7 940 with their locked 20X and 22X multipliers are going to be limited theoretically to clocks of 4400MHz, and 4840MHz...if we can even clock to 220 BCLK. Of course there are Turbo modes which increase the multiplier in certain circumstances but this is small consolation for higher end cooling when an i7 920 can all but be maxed out with a well designed water cooling loop. The i7 940 isn't as bad but with the price being such a jump, the i7 965 is the better choice.

The biggest factor with our overclocking section in a motherboard review is the fact that the memory controller is now on the CPU die. So with no more FSB and no memory controller, testing a motherboards overclocking is almost a test in futility. Now, more than ever, good BCLCKs and memory clocks will rely on the CPU used as opposed the days of old where a motherboard played the critical role in memory and FSB clocks. With that said, the motherboard is still going to play a minor role in memory clocking and processor clocking, it just won't be as dramatic a role like the Intel chipsets of past. So let's get started with seeing how high we can push this Corsair Dominator 3x2GB kit of memory at CL8.

3x2GB Maximum Memory Stability Testing

The introduction of the on-die memory controller and triple channel memory, opened the door to all kinds of possibilities on the Intel chipset. Higher bandwidth through increase throughput from adding a third memory channel, and lower latencies due to the on-die memory controller are the two biggest benefits. There is also this idea that memory needs to be limited to 1.65v otherwise damage to the memory controller will incur. This information has yet to be proven with retail CO/C1 stepping CPUs. On B1/B2 Engineering Samples, it was very much in play. Even though we don't take much caution in the 1.65v limitation for vDIMM, we still couldn't push much more than that into these modules without them failing to boot.

We are not sure quite yet whether this is a motherboard related issue or the memory simply does not like voltages above 1.65v vDIMM, but any time we set 1.7v vDIMM or higher in the BIOS, we were greeted with a lovely series of beeps equating to memory. Even still, this DDR3-1600 kit of memory had no problem running up the clocks at even 1.65v, its rated voltage. We managed a healthy 910MHz or equivalent to DDR3-1820 overclock at 8-8-8 timings. For six gigabytes of memory running at a measly 1.65v, we couldn't be more pleased. Just look at the ridiculous bandwidth in Everest in the screenshot. There will be more from this setup in the coming benchmarks. Let's now move on to our max BCLK/QPI overclocking.

Base Clock/QPI Stability Overclocking

The next item up on the list of overclocks in the BCLK/QPI clock. The reason the QPI is mentioned is because it is actually what is limiting the BCLK. In our limited testing thus far, we have found that the processor is what seems to limit this overclock and in the screenshot we can see that an i7 920 ES has been used. This is because it was able to reach 5MHz higher BCLK than our i7 965 processor was for completely stability. We can bench a slightly higher BCLK but full stability was limited to 205MHz. As we mentioned earlier, a 220BCLK is not ever guaranteed with any setup and some people will be able to clock higher, but a 200 BCLK has quickly become the standard around the forums since the i7's release. This combination has no problem clocking at 205 BLCK for an effective 3684MHz QPI clock.

The beauty of this overclock is the fact that all motherboard voltages with the exception of CPU VTT, were left at their lowest settings. Voltage adjustments did not help this setup from clocking higher and getting to this point really was quite easy. EVGA is so confident that their X58 SLI motherboard will have no problem clocking to a 200BLCK that one of their technical support representatives has posted a 'roadmap' of sorts on how to get to 200BLCK for this motherboard. That can be found here in the EVGA support forums. It is a good starting point but we found that some of the voltages were much higher than they needed to be and actually caused instability until we decreased them, so you will want to find your own sweet spot with this setup.

Overall Stability Overclocking

We have now pulled everything together and come up with our highest stable overclock with this setup keeping our previous found limitations in mind. The most important aspect of any system overclock is the processor speed and we have managed to get this 965 up to a solid 3892MHz with the Thermalright Ultra-120 eXtreme providing the cooling. This is by no means the best we have seen on air but it also isn't the worst. This processor was chosen not for its air clocking capabilities so we never really expected 4GHz - or higher - stable out of this setup. We have a nice combination of our memory at 900MHz with a nice 1.600v and the processor only reaching the high 60's or low 70's under 100% load.

For the final overclock we have increased a couple of the motherboard voltages as shown in E-LEET but the only real important voltage adjustment is CPU VTT as that is the one voltage that plays a key role in system stability. Getting a 200BCLK out of this setup sure is easy, getting a lot more out of it wasn't easy. There definitely was a hard wall at 205 with our i7 920 CPU and an equally tough wall at 200BCLK with our retail i7 965. Overall this setup is very quick and lightning fast. We will now be using this overclock in our benchmarks to compare stock settings to what the system performs like when overclocked.