Spotlight: Hyperthreading
The Clarkdale cores also have hyperthreading technology, which first appeared with the Pentium 4s and is also on Atom processors.
It’s a technique that facilitates handling of several threads by the same execution core. In the absence of hyperthreading, the core processes successively the bits of different threads that it’s sent to process. The constant transition from one thread to another gives an illusion that they’re being executed simultaneously but in actuality a lot of time is devoted to these transitions. The idea of SMT is to allow the core to work on not one but two contexts at the same time, which also means two threads truly simultaneously.
What’s the impact of SMT in practice? We measured the difference in performances in our test suite with and without SMT activated on a Core i3-540:
While there’s no gain in WinRAR and Arma2, this isn’t the case in other applications with the average gain with hyperthreading coming in at 14.7%. The biggest gain is 27.9% in MinGW compilation, followed by 22.9% in Cinema4D rendering and 21.6% in Anno 1404. While hyperthreading can sometimes have a negative impact on performance with quad cores, here this isn’t the case.
The test
For this test, we used the protocol elaborated for the Core i5 test. As you’ll remember if you’ve had a look at that test, we took advantage of the availability of the definitive version of Windows 7 to revamp the 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’ve taken the opportunity of updating 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 The VirtualDub/DiVX combos and AutoMKV/x264 have been replaced by Avidemux/x264 and MainConcept Reference/H.264, while the test files of virtually all the tests have changed or been modified (higher rendering resolution for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 games, we’ve 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 GB DDR3-1333 7-7-7
- 2x2 Go DDR3-1066 7-7-7 (si 1333 impossible)
- 2x2 Go DDR2-1066 5-5-5
- GeForce GTX 280 + GeForce 190.62
- Raptor 74 GB + Raptor 150 GB
- Creative Audigy
- Windows 7 64-bit.
