We carried out our tests on a testbed that included the following components:
- Zotac Z68-ITX WiFi mainboard, Z68 ITX-A-E model (LGA1155, Intel Z68 Express, BIOS version 2K110809);
- Intel Core i5-2500K CPU (3.3 GHz, Sandy Bridge, LGA1155);
- 2 x 2048 MB DDR3 SDRAM Patriot Extreme Performance Viper II Sector 5 Series PC3-16000, PVV34G2000LLKB (2000 MHz, 8-8-8-24 timings, 1.65 V voltage);
- MSI N570GTX-M2D12D5/OC graphics card (Nvidia GeForce GTX 570, GF110, 40 nm, 786/4200 MHz, 320-bit GDDR5 1280 MB);
- Kingston SSD Now V+ Series (SNVP325-S2, 128 GB);
- Scythe Samurai ZZ (SCSMZ-2000) CPU cooler;
- ARCTIC MX-2 thermal interface;
- CoolerMaster RealPower M850 PSU (RS-850-ESBA);
- Open testbed built using Antec Skeleton system case.
We used Microsoft Windows 7 Ultimate SP1 64 bit (Microsoft Windows, Version 6.1, Build 7601: Service Pack 1) operating system, Intel Chipset Software Installation Utility version 220.127.116.110, Nvidia GeForce Driver 280.26 graphics card driver.
Operational and Overclocking Specifics
We didn’t experience any serious problems during system assembly on Zotac Z68-ITX WiFi. We use Scythe Samurai ZZ cooler for mini-ITX systems instead of our traditional Scythe Mugen 2. This cooler fit perfectly onto our board and even left enough room for DIMM modules with tall heat-spreaders. However, with default settings Intel Turbo Boost technology didn’t work for some reason, even though it was enabled in the BIOS. The processor clock frequency multiplier didn’t increase and remained at 33x at all times. However, it is already a second Zotac Z68-ITX WiFi mainboard in our lab and the previous one didn’t have any problems with Turbo. Therefore, after a few failed attempts to clear the settings and force the clock frequency multiplier to go up, we reflashed the BIOS several times and Intel Turbo Boost finally started working normally.
Our test Intel Core i5-2500K processor can be overclocked to 4.7 GHz frequency. We failed to go that far on our Zotac Z68-ITX WiFi based system, because the stability wasn’t there. First we started lowering the frequency and voltage trying to find the sweet spot for stable operation, but during one of the following stability checks Zotac Z68-ITX WiFi board burned down and took our processor with it. This is when we received a new Z68-ITX WiFi sample from Zotac. But this time we decided to change our overclocking strategy and move up from lower frequencies to higher and not the other way around, as we did before. Besides, we haven’t yet had a chance to check out the full potential of the new processor. Besides its maximum overclocked frequency we only know that it can work at 4.5 GHz without any Vcore increase but with the enabled technology for counteracting the core voltage drop under heavy load. We obtained the same exact result during our MSI Z68A-GD80 (G3) mainboard review: we used this approach to ensure that all processor power-saving technologies will stay up and running on MSI board.
Zotac mainboard doesn’t have a BIOS parameter that would allow it to counteract the voltage drop under heavy loads. In this case, namely without VDroop or Load-Line settings in the BIOS and without increasing the processor core voltage, the maximum clock frequency attainable on our particular CPU was 4.3 GHz. However, unlike MSI mainboards, the Zotac ones have no problems with power-saving technologies that is why we can easily push the processor Vcore a little higher. However, it is also important to remember that our cooling system is weaker than usual, so it is crucial to monitor all temperatures very closely. As a result, when we increased the CPU Vcore by 0.1 V, Zotac Z68-ITX WiFi mainboard managed to overclock our processor to 4.5 GHz. Further voltage increase didn’t make any sense and was hardly possible, because even in an open testbed the CPU temperature under load rose to 88°C. Of course, inside a closed system case the temperature will most likely get beyond 90°C, so only a very well-ventilated system case can actually guarantee long-term stability even at this relatively low frequency. As for the memory, the board couldn’t get it to work stably at 1866 MHz, but had it running perfectly fine at 1600 MHz with 6-6-6-18-1T timings.
We always overclock our system so that it could be used in this mode for a long time. At the same time we do not try to make our life easier by disabling some of the mainboard features, such as additional controllers, for example. We also do our best to make sure that all processor power-saving technologies stay up and running normally. So, in this case all power-saving technologies were working fine even during overclocking, so the processor Vcore and clock multiplier were dropping in idle mode as they are supposed to.