The Supermicro C7Z370-CG-IW Motherboard Review: SM's First Mini-ITX Gaming Board

Overclocking

Experience with the SuperO C7Z370-CG-IW

I will be the first to admit I went into overclocking on the SuperO board with tempered expectations, but mostly because of the board's size and the fact that second tier manufacturers often have issues when it comes to overclocking. Mini-ITX boards aren't typically geared towards pushing overclocks very far, but many still can. In the case of the C7Z370-CG-IW, it was a disappointing outcome. In fact, in our stock testing, we ran into power limit issues with the AVX based multithreaded testing which needed manual intervention to raise the default 65W power limit so its performance would match the other board's performance (*Fixed in BIOS R1.1).

Overclocking using the SuperO Booster software presets didn't give us a huge increase either. The auto-tuning function yielded a 48x single-core result and 4.3 GHz AVX load using all cores/threads at 1.28V. The OC Mode function has a 4.7 GHz single core,  which is the stock boost and runs AVX loads at 4.2 GHz (no offsets). So long as the power limits were raised, which setting the CPU multiplier manually seems to do automatically, then it ran without a hitch. 

In the end, we were able to push the CPU to 4.4 GHz using all cores/threads without an AVX offset. After 4.4 GHz, we would see current limit throttling which then cuts the clock speed back. Running into current limits isn't anything new, however, the BIOS doesn't have options to raise current limit so we were, for all intents and purposes, stuck with the limits from the factory. Perhaps in the future SuperO will release a BIOS with the ability to raise the current limits which will extend overclocking headroom. Along those lines, the board did have significant vdroop. With the voltage set to 1.2V in the BIOS, load voltage dropped to 1.12V according to software. Typically this is combated with load line calibration (LLC) settings in the BIOS, however, this SuperO board does not appear to have LLC options. Vdroop isn't a big deal, in fact, it is part of the Intel specification, but many users prefer to minimize or eliminate vdroop which cannot be done on this board with the current BIOS. 

While a lot of the features and options are found in the C7Z370-CG-IW BIOS, we do have a couple of items missing that would help with overclocking. That said, we also have to realize this is a Mini-ITX sized board and really not intended for pushing overclocks. I do hope with future BIOS releases these options show up so the board is able to flex some of its muscle hidden underneath. 

Overclocking Methodology

Our standard overclocking methodology is as follows. We select the automatic overclock options and test for stability with POV-Ray and OCCT to simulate high-end workloads. These stability tests aim to catch any immediate causes for memory or CPU errors.

For manual overclocks, based on the information gathered from the previous testing, starts off at a nominal voltage and CPU multiplier, and the multiplier is increased until the stability tests are failed. The CPU voltage is increased gradually until the stability tests are passed, and the process repeated until the motherboard reduces the multiplier automatically (due to safety protocol) or the CPU temperature reaches a stupidly high level (90ºC+). Our test bed is not in a case, which should push overclocks higher with fresher (cooler) air.

Overclocking Results

The C7Z370-CG-IW took our i7-8700K to 4.4 GHz. We mentioned earlier we hit CPU clock speed limits in what I would describe as prematurely and was stopped dead in our tracks because of it. The CPU should be able to reach 5 GHz+ as it did on the NZXT N7. But until current limits are raised, there is a glass ceiling for overclocking on the board. The good news is even though the board supports up to DDR4-2666, it didn't have any issues running the XMP profile for our second set of sticks rated for 3200 MHz. But until the current limit is raised, overclocking is quite limited.