So what works and what doesn't with the Intel P55 and Lynnfield processors when it comes to Linux? Well, we have just had the hardware for about a week, but so far the experience is relatively pleasant after first sorting out a few issues. When it comes to the Intel P55 motherboard we tested, the Intel DP55KG, the motherboard had worked with Ubuntu 9.04 and its Linux 2.6.28 kernel except for the Gigabit Ethernet adapter was not detected. When upgrading to Ubuntu 9.10 Alpha 5 with the Linux 2.6.31 kernel, the network adapter was now supported. One area also lacking in the Linux support for the Intel Lynnfield / Ibex Peak with both the motherboard and the CPU is the lack of any LM_Sensors system monitoring support for being able to read the fan speeds, temperatures, and voltages. Nothing was detected by LM_Sensors found in the latest Ubuntu 9.10 code. Besides those two caveats, the Intel P55 motherboard had ran fine on Linux.
When it comes to the new Intel Core i5 / Core i7 processors on Linux, initially we were plagued with sporadic performance issues. On some test runs with the Phoronix Test Suite the Lynnfield processors would run very well, but when running the tests again just seconds later, the performance results would be wildly and severely impaired. This had happened with both the Core i5 750 and Core i7 870. When facing these problems, Enhanced Intel SpeedStep Technology (EIST) was disabled, and we tried a few other tweaks, but the problems persisted with both Ubuntu 9.04 and the Ubuntu 9.10 development snapshot.
During this early testing, we also found that the CPU core frequencies never increased to their Intel Turbo Boost frequencies when they were encountering a load. Intel's Turbo Boost Technology was not working under Linux. Once we disabled Turbo Boost from the BIOS, our sporadic performance problems were eliminated too. The performance numbers stopped fluctuating and dropping so much between runs and there were finally stable performance figures. Turbo Boost never boosted the performance under Linux or even the frequencies for that matter, but just seemed to cause some problems in our early testing. It would be nice though to see proper Intel Turbo Boost Technology for Linux, but again, as long as its disabled, the CPU should function and performance as expected for its base frequency.
Aside from these mentioned items, our testing thus far has revealed no other Linux problems with the Intel DP55KG and the Core i5 750 / Core i7 870. At the end of the day, the Intel platform will run fine under Linux, but there's a few hiccups right now, but let's see how it performs... Check out our Core i5 750 / Core i7 870 benchmarks.