UPDATE 1st August 2015 - Added a hexa-core version of the CPU skin. If you have any suggestions or questions concerning the skins, you can contact me on the Rainmeter forums. If you don't fancy the black/gold background you can change to a transparent background in the file. The best Windows alternative is Sidebar Diagnostics, which is both free and Open Source. Switch between variants by right-clicking anywhere on the skin and selecting 'Variants'. There are many alternatives to Rainmeter for Windows if you are looking for a replacement. All the variants have a gauge showing overall CPU usage and smaller gauges for RAM and SWAP memory usage. This should mean you won't get any errors even if you have a single core or three cores. Each variant detects the number of cores and adjusts the settings for each tube accordingly. One shows tubes for CPU usage on up to 4 cores, one for six cores, one with tubes for up to 8 cores and one shows 8 tubes with the usage of cores 1-4 mirrored up and down. I attached zipped copies of the HWinfo skin and the ALl CPU Meter config files. CPU is an AMD FX-8350 and it has just the CPU 0 temp sensor. What you get here is four variants of the CPU-RAM-SWAP skin. HWinfo shared memory is enabled and I can see the CPU 0 sensor and all of it's entries, the temps are reading live in the shared memory viewer too, and I am fairly sure I have the values entered correctly. I've uploaded it as a separate file for those that don't want any of the other skins.
This 6 and 8-core version of the CPU-RAM-SWAP skin is an addition to the original Cogs, Tubes and Gauges collection of Rainmeter skins.