I posted some of these tips on reddit for speed improvements on Dolphin and PCSX2, but made a few changes:
1. Change Windows screen resolution to 640x480. This mean less heat = less throttling.
2. Change quad core to tri core or dual core by disabling 1 or 2 cores at msconfig. Dolphin is more optimized for dual cores, and again less cores = less heat = less throttling. (in fact, it only uses 2 cores, so more than 2 is really pointless and just wastes energy and creates more heat)
3. Download the latest build of Ishiiruka Dolphin (a faster version of dolphin from here:https://forums.dolphin-emu.org/Thread-unofficial-ishiiruka-dolphin-custom-version). Go to settings and turn on DirectX12 (more optimized on ishiiruka), fast efb, ignore format changes, efb to texture only, and full async shader. Also on advanced config, lower the cpu override to 70%.
1. Pretty much the same as above. But on the gsdx ini text file add this line: UserHacks_DisablePartialInvalidation=1
2. Download the latest build of PCSX2 and use OpenGL, since it is the fastest on PCSX2 right now.
3. On emulation settings turn speedhacks to level 3 (balanced) or level 4 (Agressive). Also, turn on MTVU speedhack on certain games. It speed up games on a quad core processor.
*Note Unlike Dolphin, PCSX2 takes advantage of quad core, BUT due to that it can also throttle the Atom CPU more. So I recommend to disable only 1 core (tri core) or experiment with different games.