RWEverything ("Read and Write Everything") is a powerful tool which can display a host of low-level technical details about your PC hardware, as well as allowing you to write to most of your devices. It's just as complicated as it sounds, but don't give up just yet - there are a few features here that anyone can use.
If you need to know more about your RAM, for example, just click the SPD button, then the Summary tab. RWEverything interrogates your memory's Serial Presence Detect (SPD) tables and tells you everything you need to know: RAM type, size, speed, part number, even memory timings.
Clicking the ATA/ATAPI button provides similar details about your connected drives. You'll see a drive model name, serial number, size, firmware revision and speed, along with useful information about its features. (If you're curious whether a drive supports S.M.A.R.T., say, you'll find the information here.)
The USB report can be even more useful, as it doesn't just tell you about your USB hubs and ports, but it also delivers a vast amount of information about any connected devices. Even PC experts won't understand most of it, but there are enough nuggets to be helpful. We plugged in a smartphone and RWEverything gave us its model name, manufacturer, serial number, and technical details on its various capabilities (imaging, the modem and more).
If you really know what you're doing then there's plenty more here, with in-depth reports on your monitor, PCI devices, SMBIOS structures, ACPI tables and so on.
RWEverything goes even further, though, enabling you to write to devices as well as read them. This isn't something you can do without making some effort; typically you'll have to double-click a character in the hex view, enter another value and click "Done". But it is still possible, and if you get this wrong then you could damage your system, so pay close attention and don't carry out any action with RWEverything unless you're completely sure that it's safe.