Overclocking without Processor Vcore Increase

While in nominal mode we didn’t have any problems and didn’t notice anything specific, we did encounter numerous peculiarities during overclocking. It was a very diverse experience that took us from success to some failures and then back up to victory again.

First let’s check out the ability of MSI Eclipse Plus mainboard to work at high base frequency settings. For that purpose we lowered processor clock frequency multiplier to the minimal possible setting of 12, set the lowest memory divider and raised the base frequency to 210MHz. The system booted the OS and passed a brief stability test successfully. At 215MHz base frequency we managed to boot, but had some errors pop up during stability tests. However, we didn’t try too hard to get the system to work at 215MHz anyway. Even 210MHz was more than enough to overclock our Intel Core i7-920 processor sample to its maximum and MSI Eclipse Plus mainboard would obviously be no bottleneck in this case. Great result!

Then we decided to check if the board could make the memory work at high frequency, too. If we simply selected an X.M.P. profile in the mainboard BIOS that set the memory frequency at 1867MHz, MSI Eclipse Plus tried to boot but without luck. It was not good, but not too bad either, because the board could boot just fine and passed all tests when we set the 1867MHz memory frequency manually. Generally, this was all we needed to know at that point. The board supported high base frequency settings and high-frequency memory. Now all we needed to do was combine these two features of MSI Eclipse Plus and make them work to our advantage.

At first let’s check out how well MSI Eclipse Plus can overclock without any processor Vcore increase. We enable “CPU Load Line Calibration”, set the base frequency at 181MHz, memory frequency is 1810MHz and timings – 8-8-8-22-1T. We have checked out these settings multiple times on other mainboards before; however, MSI Eclipse Plus starts but is unable to load the operating system, not to mention passing any sort of tests. Frustrating. Let’s try to find out what is going on. We lower the memory frequency and the board loads Windows just fine. I get it! It must have been the memory! We are going to get back to this matter later, and now we have to make sure that at 181MHz base frequency the CPU remains stable. No way, the BSOD appeared almost immediately after we started the test. So, it appears that not only the memory hinders overclocking success but also the CPU is unable to work stably with the base frequency increased to 181MHz. Very frustrating!

At first I thought that it could be “CPU Load Line Calibration” function that wasn’t working properly. It was supposed to prevent processor core voltage from dropping under heavy load keeping it around the nominal 1.225V. However, during our tests the CPU core voltage dropped to 1.128V and with disabled “CPU Load Line Calibration” it dropped even lower – to 1.1V. Of course, the CPU can’t work stably at a low voltage like that when it is overclocked to 3.8GHz. This is exactly the frequency that we get with the base frequency at 181MHz and 21x clock multiplier provided by Turbo Boost technology. It turned out that the reason for all of this was specific implementation of Turbo Boost technology during overclocking on MSI Eclipse Plus.

In our case, when the CPU is not overclocked, its frequency multiplier is increased to 21x under any workload. During overclocking, the board will continue to act the same way only under relatively low load of four threads or less. The processor core voltage in this case stays around 1.216-1.22V, which is very close to the default 1.225V. It means that “CPU Load Line Calibration” is working. If we load the CPU heavier, with five or more computational threads, the clock multiplier doesn’t increase, it remains equal to 20. The processor Vcore is way below the nominal value in this case, staying around 1.128-1.132V with “CPU Load Line Calibration” enabled and drops even more if we disable it. In fact, the processor clock frequency multiplier could increase to 21 guaranteed only under relatively low load of 1-2 threads; at 3-4 threads the multiplier will mostly be at 21, but will also go down to 20 causing corresponding drop  in processor Vcore.

This is when we should remind ourselves what the idea of Intel Turbo Boost technology is to begin with. If the power consumption and temperature of an overclocked processor are within acceptable limits, its clock frequency multiplier can be increased by one or even two. Of course, this situation occurs when the workload is fairly low. If all four processor cores are busy and each is working on two threads due to Hyper-Threading technology, then the power consumption of a CPU with an increased clock multiplier will most likely get beyond acceptable maximum and the multiplier will go back to its nominal value. Looks like MSI Eclipse Plus demonstrates the “correct” implementation of Turbo Boost technology. Unlike many other mainboards that increase the clock frequency multiplier under any load and disregard the power consumption altogether, MSI Eclipse Plus mainboard monitors the workload level and corrects the processor clock multiplier accordingly. The only disadvantage here is that we lose some of the performance due to supposedly “correct” implementation of Turbo Boost technology. While on most other mainboards the CPU always works with increased clock multiplier, the CPU on MSI Eclipse Plus has a nominal multiplier and hence lower operational frequency.

We tried to lock the multiplier at 21x by disabling “Intel EIST” in the BIOS. No luck, the CPU multiplier was at 21 in idle mode and didn’t change, but then immediately dropped to 20 under multi-threaded load. “Overspeed Protection” parameter from “CPU Feature” sub-section could theoretically help here. According to its description, it lowers the CPU frequency under heavy load. However, even when we disabled it, the mainboard still acted the same. As a result, you can only push the base frequency as far as 176MHz without losing processor stability. But this is not the end of it yet. Unfortunately, during overclocking MSI Eclipse Plus doesn’t work with memory as well as some other boards.

First of all I was very surprised to see that the board set 9-9-9-24-2T timings for high-frequency memory. Other mainboards also set 9-9-9-24, but with 1T. I cannot remember a single time when I had to replace 2T with 1T on any Intel X58 Express based mainboard. However, it is no big deal. Remember the X.M.P. technology that doesn’t work properly on MSI Eclipse Plus in auto mode, but you can still set high memory frequencies manually without any problems? Here is the same thing: you can manually set 1T and MSI Eclipse Plus will work just as good as any other mainboard. Too bad, though, that we will still have to increase the primary timings.

We first tested Kingston HyperX KHX14900D3T1K3/3GX memory modules on Gigabyte GA-EX58-Extreme mainboard. This memory has been participating in our mainboard tests since then and the results obtained before get confirmed over and over again. Namely, with the base frequency increased to 181MHz this memory can work at 1810MHz frequency with 8-8-8-22-1T timings or even 8-8-8-20-1T timings. When we increase the base frequency on MSI Eclipse Plus mainboard to 176MHz,t eh memory frequency can only be increased to 1760MHz, but even in this case we can’t set CAS Latency 8. We could only achieve stability with 9-9-9-24-1T timings.

Not too good, as it will make our CPU work at 3.7GHz only under small workload and as soon as the number of threads exceeds 5 the clock multiplier will immediately drop to 20x.

The fact that all Intel CPU power-saving technologies remain up and running is a weak compensation for lower CPU frequency, lower memory frequency and higher timings on MSI Eclipse Plus mainboard compared to other solutions.