We performed all our tests on a testbed built with the following components:
- Gigabyte GA-Z77X-UP5 TH rev. 1.0 (LGA1155, Intel Z77 Express, BIOS version F3);
- Gigabyte GA-Z77X-UP4 TH rev. 1.0 (LGA1155, Intel Z77 Express, BIOS version F4);
- Intel Core i5-3570K CPU (3.6-3.8 GHz, 4 cores, Ivy Bridge rev.E1, 22nm, 77 W, 1.05 V, LGA 1155);
- 2 x 4 GB DDR3 SDRAM Corsair Vengeance CMZ16GX3M4X1866C9R (1866 MHz, 9-10-9-27 timings, 1.5 V voltage);
- Gigabyte GV-T797OC-3GD (AMD Radeon HD 7970, Tahiti, 28 nm, 1000/5500 MHz, 384-bit GDDR5 3072 MB);
- Crucial m4 SSD (CT256M4SSD2, 256 GB, SATA 6 Gbps);
- Scythe Mugen 3 Revision B (SCMG-3100) CPU cooler;
- ARCTIC MX-2 thermal interface;
- Enermax NAXN ENM850EWT PSU;
- 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, AMD Catalyst graphics card driver version 12.4.
Operational and Overclocking Specifics
The convenient layout of both mainboards made it super easy to assemble the test systems. Unfortunately, we had to give up the idea of testing Gigabyte GA-Z77X-UP4 TH mainboard right from the beginning, because the board just wouldn’t start. The fans would power up and the LEDs will turn on for a fraction of a second, but then the system would immediately shut down. In a short while we had to prematurely stop the testing of the Gigabyte GA-Z77X-UP5 TH, too. Unlike the previous mainboard model it didn’t have any startup issues, but all of a sudden it refused to work with our Gigabyte GV-R797OC-3GD graphics card. Well, unexpected things do happen, so we declared both these mainboards defective and decided to postpone our review of Gigabyte GA-Z77X-UP4 TH and Gigabyte GA-Z77X-UP5 TH mainboards until we got operational replacement samples. But you can’t imagine our shock, when the new Gigabyte GA-Z77X-UP4 TH mainboard also refused to start in exact same manner as the previous one! At that point it became obvious that there must be some kind of compatibility issue going on in our testbed. Indeed! Our Cooler Master RealPower M850 power supply unit was identified as the source of our problems. As soon as we replaced it with Enermax NAXN ENM850EWT, all four mainboards started working flawlessly. Gigabyte GA-Z77X-UP4 TH got rid of the strange startup problems, while the external graphics card stopped shutting down in our Gigabyte GA-Z77X-UP5 TH based system.
I have to admit that despite the happy ending, this situation concerned me a lot. I would prefer the boards to be defective, than face the compatibility issues. The defect may occur at the production stage or the board may get damaged in transit, but even though it may be unpleasant experience, the board will be replaced under warranty terms in both cases. However, in case of incompatibility with any of the existing system components, the mainboard is formally operational, and in this case the users are responsible for changing the system configuration and replacing incompatible components on their own and at their own expense. We have been using Cooler Master RealPower M850 power supply unit for about two years. Over this period of time we tested over 60 mainboards of all kinds and have never had any issues like that. The PSU is perfectly fine, and works normally with any mainboards, including other Gigabyte mainboards, except for these two particular models. To be fair I have to say that two years ago we switched to this specific PSU for the same exact reason – incompatibility. However, back then it was an Asus mainboard (maybe a defective specific unit) that wouldn’t work properly ever after we replaced the power supply unit. This time we are not talking about any bad luck incidents: new Gigabyte mainboards of these particular models do not work with this particular power supply unit, which was confirmed by testing two identical mainboards for each model. The problem could be the processor voltage regulator circuitry on these boards, and maybe the IR3550 PowIRstage components in particular.
As soon as we replaced the PSU, we had absolutely no issues of any kind in nominal mode as well as during overclocking experiments. The boards display startup image with the list of “hot” keys. It doesn’t make sense to disable the startup image, because the boards do not report any useful information during system boot-up anyway.
We overclocked our processors to its maximum frequency of 4.6 GHz on Gigabyte GA-Z77X-UP4 TH having increased the memory frequency to 1867 MHz at the same time.
Strange as it might seem, but Gigabyte GA-Z77X-UP5 TH couldn’t do the same. Either the voltage was set too low and it caused errors, or the voltage was too high and the CPU temperature got dangerously close to 100 degrees C. So, we had to stop at 4.5 GHz, but we had absolutely no problems when we increased the memory frequency and adjusted the timings.
Now I just have to remind you that we always overclock mainboards in such a way that they could be used permanently in this mode. Therefore we do not try to make our life easier by disabling any of the mainboard’s features, e.g. onboard controllers, and try to keep the CPU’s power-saving technologies up and running. This time we did exactly the same thing. All Intel power-saving technologies remained enabled and automatically lowered the processor Vcore as well as clock frequency multiplier in idle mode.