The CPUs
For this test, Intel supplied us with two models:
- Core i7-870, 2.93 GHz, $562
- Core i5-750, 2.66 GHz, $196
From left to right: LGA775, LGA1156 and LGA1366. As you can see, an LGA1156 processor is the same size as an LGA775.
Energy consumption
Energy consumption was measured in two places: processor consumption alone at the ATX12V socket and with a clip-on ammeter and total consumption with a power meter at the wall socket, always loading the machine with Prime 95. This means that other components such as the graphics card or the hard drive are in idle when these readings are taken.
In the case of the readings at the ATX12V, because of the different ways in which the CPUs are supplied, on a Phenom II the memory controller (not integrated on the Core 2s) which consumes between 10 and 15W in charge is taken into account, while on the Core i7 it isn’t (also the case for the L3), the uncore being supplied via the ATX standard.
The new Core i5/i7s consume more than the LGA1366s in idle, in spite of all the energy economy features being activated: perhaps integration of the PCI-Express controller is the difference here. In load, energy consumption is higher than on the LGA1366 platform, which can be explained by the fact that the Turbo mode goes further. Note, moreover the small difference between 4x and 8x Prime on the Corei7-870.
At the wall socket the LGA1156 platform gets a great score in idle, thanks to the single P55 southbridge on the motherboard. It does better than with the socket 775 platform which is truly remarkable. In load of course it’s another story given the energy demands of the Core i5s/i7s, but the Core i7-870 configuration is for example more economical than the Core i7-920 while the processor on its own consumes more.
Overclocking
Given the fact that they already consume a lot of energy, we limited overclocking to 1.3V in the bios (1.27-1.3V in practice) for each of our processors, which is about 0.1V up on the base voltage.
In both cases we managed a stable 3.8 GHz with a bus clock of 190 MHz for the i5 and 173 MHz for the i7. There is a decent margin for overclocking then but you’ll need to fit yourself out with the right cooling to go any further.
The test
For this test, we took advantage of the availability of the RTM version of Windows 7 to redesign our test protocol. The OS first then: we’re now using a 64-bit version of Windows 7, which means that all software available in 64-bit mode is tested in this mode.
We have taken the opportunity to update the software, which means 3ds max is now tested in version 2010, Min GW and WinRAR (3.8 up to 3.9) have been updated, as have After Effects (CS3 up to CS4) and Nuendo (4.2 up to 4.3). The VirtualDub/DiVX combos and AutoMKV/x264 have been replaced by Avidemux/x264 and MainConcept Reference/H.264, while the test files of virtually all the tests have changed or been modified (higher rendering resolution for example).
In terms of the games, we have decided to retain Crysis 1.2 and its ultra-heavy CPU test but to retire World In Conflict and replace it with more recent and demanding games: Arma 2, Grand Theft Auto IV and Anno 1404 join the protocol. So as to show up processor differences to a maximum, we set all graphics options to a max so as to load right up, at the same time as limiting resolution to 800*600 so as to eliminate any smoothing due to the power of the mono-GPU solution used on the test configuration.
The configurations are as follows:
- ASUSTeK P5QC (LGA775)
- Intel DP55KG (LGA1156)
- Intel DX58SO (LGA1366)
- ASUSTeK M4A79-T (AM3)
- 2x2 Go DDR3-1333 7-7-7
- GeForce GTX 280 + GeForce 190.62
- Raptor 74 GB + Raptor 150 GB
- Creative Audigy
- Windows 7 64 bit
