Graphics Core Overclocking
Intel H67 chipset designed for use with graphics core in the Sandy Bridge CPUs doesn’t support overclocking. It provides no access to the multiplier for the CPU as well as memory frequency. However, Intel H67 allows adjusting the graphics core frequency. Mainboards based on this chipset usually have an option showing how high the graphics core can be overclocked in Turbo mode.
And this option is not just for show. Intel limits the graphics core frequency in coordination with the TDP of the corresponding processor models, which means that it is quite possible to overclock with proper cooling.
We performed overclocking experiments with several different Core i5 processor samples and found that with a slight increase of the graphics core voltage we could easily push its frequency to 1.5 GHz. In other words, the GPU inside sandy Bridge processors doesn’t have that big of an overclocking potential, but we can still count on at least 30-40% graphics performance improvement during overclocking.
However, this is not the case for Core i7 CPU models. The frequency of Intel HD Graphics 3000 core inside them is almost at the maximum already.
Testbed Configuration and Methodology
During our today’s test session e decided to compare the performance of the new Intel HD Graphics 2000 and Intel HD Graphics 3000 accelerators integrated in Sandy Bridge processors against the competitor integrated GPUs and entry-level graphics cards. There are currently two integrated graphics platforms for desktops in the market that could be considered worthy competitors to Sandy Bridge: Socket AM3 with AMD890GX chipset and LGA1156 with Clarkdale processors and Intel H57/H55 chipset (we do not take into account their numerous modifications here). These will be the today’s competitors to the systems based around second-generation Core i5 processors with Intel HD Graphics 2000 and Intel HD Graphics 3000 cores. Moreover, we also included inexpensive discrete graphics accelerators from AMD: Radeon HD 5450 and Radeon HD 5570.
Since we couldn’t compare the integrated graphics ores in CPUs of the same computational capacity, we used Socket AM3 and LGA1156 processors with the today’s highest clock rate, which could at least somehow compete against Sandy Bridge. Note that we had to work with two Clarkdale models – Core i5-680 and Core i5-661. The former has the highest clock frequency, while the latter features higher –performance graphics core. In the AMD platform we used a quad-core Phenom II X4 975. As for Sandy Bridge, we took Core i5-2400 to test Intel HD Graphics 2000 and Core i5-2500K to test Intel HD Graphics 3000. As for the discrete graphics cards, we tested them in the same LGA1155 system with the Intel Core-i5 2500K processor.
As a result, we ended up putting together the following testbeds:
- AMD Phenom II X4 975 (Deneb, 4 cores, 3.6 GHz, 6 MB L3);
- Intel Core i5-2500K (Sandy Bridge, 4 cores, 3.3 GHz, 6 MB L3);
- Intel Core i5-2400 (Sandy Bridge, 4 cores, 3.1 GHz, 6 MB L3);
- Intel Core i5-680 (Clarkdale, 2 cores, 3.6 GHz, 4 MB L3);
- Intel Core i5-661 (Clarkdale, 2 cores, 3.33 GHz, 4 MB L3);
- ASUS M4A89GTD PRO/USB3 (Socket AM3, AMD 890GX + SB850, DDR3 SDRAM);
- Gigabyte GA-H57M-USB3 (LGA1156, Intel H57 Express);
- Gigabyte GA-H67MA-UD2H (LGA1155, Intel H67 Express).
- Memory: 2 x 2 GB DDR3-1333 SDRAM, 9-9-9-27 (Kingston KHX1600C8D3K2/4GX):
- Graphics cards:
- ATI Radeon HD 5570;
- ATI Radeon HD 5450.
- Hard drive: Kingston SNVP325-S2/128GB.
- Power supply unit: Tagan TG880-U33II (880 W).
- Operating system: Microsoft Windows 7 Ultimate x64.
- Intel Chipset Driver 18.104.22.1689;
- Intel Graphics Driver 22.214.171.124.2279;
- ATI Catalyst 11.1 Display Driver.
We tested Intel HD Graphics 2000 and Intel HD Graphics 3000 graphics cores in two modes: at nominal (for most desktop processors) frequency of 1100 MHz and at an overclocked frequency of 1500 MHz.