We carried out our tests on a testbed that included the following components:
- Mainboard: Gigabyte GA-Z68XP-UD3-iSSD rev. 1.0 (LGA1155, Intel Z68 Express, BIOS F5);
- Processor: Intel Core i5-2500K (3.3 GHz, Sandy Bridge, LGA1155);
- Memory: 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);
- Graphics card: MSI N570GTX-M2D12D5/OC (Nvidia GeForce GTX 570, GF110, 40 nm, 786/4200 MHz, 320-bit GDDR5 1280 MB);
- Hard drive: Kingston SSD Now V+ Series (SNVP325-S2, 128 GB);
- Cooling system: Scythe Mugen 2 Revision B (SCMG-2100) CPU cooler and an additional 80x80 mm fan for cooling of the area around the CPU socket during overclocking experiments;
- Thermal interface: ARCTIC MX-2;
- Power Supply Unit: CoolerMaster RealPower M850 (RS-850-ESBA);
- System case: 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 22.214.171.1240, Nvidia GeForce/ION Driver 280.26 graphics card driver.
Operational and Overclocking Specifics
You won’t find any changes in the list of our testbed components compared to those that we used in our earlier tests of LGA1155 mainboards, but there is a difference. A Zotac Z68-ITX WiFi mainboard failed during our overclockability test, unfortunately. This happens once in a while but, what is a much rarer occurrence, it damaged our CPU, too. Therefore we had to take another sample of the Intel Core i5-2500K processor and examine its overclocking potential first. We did this with an MSI Z68A-GD80 (B3) mainboard which is good (even though not energy-efficient) at overclocking CPUs and memory modules. The second sample of the CPU proved to be inferior to the first one in terms of overclocking potential. It could work at 4.7 MHz whereas the first one at 4.8 GHz under the same conditions.
We've noticed in our earlier reviews that LGA1155 CPUs are rather easy to overclock but hard to make sure they are stable. Without stability, there is no point in overclocking. We used to run the LinX tool, a graphical interface for the Intel Linpack test, as a stability test for older CPUs. However, it wasn't good for LGA1155 CPUs because it ran smoothly where Prime95 would immediately produce errors. Prime95 is not a handy tool as it takes quite a lot of time to complete a stability test. Moreover, we eventually found out that Prime95 did not guarantee absolute stability, either. As a result, we now return to LinX version 0.6.4 but use modified Lanpack libraries. This modification is a much better stability test for overclocked CPUs, so we are going to use it in our reviews from now on.
This is to confirm that MSI mainboards are good at overclocking CPUs but do not do that optimally. They do not support energy-efficient overclocking: the CPU frequency multiplier is lowered in the idle mode but the mainboard still supplies a high voltage to the CPU.
The Gigabyte GA-Z68XP-UD3-iSSD mainboard is just as good as the MSI mainboard in terms of CPU overclocking. It made our CPU stable at a clock rate of 4.7 GHz. Unfortunately, it wasn't that good in terms of memory overclocking. The Gigabyte couldn't overclock our memory to 1866 MHz as some of the best mainboards we had tested, but we even had to set the timings at 7 to keep the memory modules stable at 1600 MHz. We have to admit we’ve only had such a poor result with some of Gigabyte's Z68-based mainboards.
Like most other modern mainboards, the GA-Z68XP-UD3-iSSD keeps all of Intel’s power-saving technologies up and running even when overclocked. In idle mode, it lowers not only the CPU frequency multiplier but also its voltage.