My answer to the original question:
Set the graphics settings to the lowest possible, 1x internal resolution(1xIR), no AA, no nothing. I have no idea how fast your GPU is, but since most integrated graphics is fast enough for 1xIR, it should also be fast enough for that. If the game runs fine with 1xIR, and not with let's say 3xIR, you want to upgrade the GPU. If the game doesn't run fine that way, you could get a GTX 1080 Ti, and it still wouldn't run fast, you'd need to upgrade the CPU.
About the benchmarks:
The new amd CPU being about 2x as fast as the old ones sounds reasonable. The IPC(instructions per clock) are really bad on the old amd CPUs, and Dolphin needs IPC more than anything, as long as you have a quad core CPU. Well, that is even speculation on my part, a dual core CPU with high IPC might be faster than a quad core CPU with slightly lower IPC. That being said, it's important that the benchmarks were run with the same version of Dolphin. I would only rely on the old one, as it's just for hardware comparision anyways. If the newer amd CPU benchmark result comes from the newer benchmark, it's totally useless. I'm too lazy to check which one was used.
As for the Last Story:
There's a speedhack for the game(based on a very outdated version of Dolphin):
https://forums.dolphin-emu.org/Thread-the-last-story-speedhack
which might be integrated now in this build(it was at one point):
https://forums.dolphin-emu.org/Thread-unofficial-ishiiruka-dolphin-custom-version
(no idea if it's enabled by default though)
The speedhack allows you to use efb2tex instead of efb2ram for the game, which is up to a 100% performance increase, depending how badly your GPU handles the game. Now the important part: With this increase, the game might be playable on an intel CPU(Haswell+) or Ryzen CPU at 4Ghz, anything lower is likely still not fast enough.
Keep the forum rules in mind please, all further discussion about those 2 builds has to happen in those threads and not in this thread here.
Set the graphics settings to the lowest possible, 1x internal resolution(1xIR), no AA, no nothing. I have no idea how fast your GPU is, but since most integrated graphics is fast enough for 1xIR, it should also be fast enough for that. If the game runs fine with 1xIR, and not with let's say 3xIR, you want to upgrade the GPU. If the game doesn't run fine that way, you could get a GTX 1080 Ti, and it still wouldn't run fast, you'd need to upgrade the CPU.
About the benchmarks:
The new amd CPU being about 2x as fast as the old ones sounds reasonable. The IPC(instructions per clock) are really bad on the old amd CPUs, and Dolphin needs IPC more than anything, as long as you have a quad core CPU. Well, that is even speculation on my part, a dual core CPU with high IPC might be faster than a quad core CPU with slightly lower IPC. That being said, it's important that the benchmarks were run with the same version of Dolphin. I would only rely on the old one, as it's just for hardware comparision anyways. If the newer amd CPU benchmark result comes from the newer benchmark, it's totally useless. I'm too lazy to check which one was used.
As for the Last Story:
There's a speedhack for the game(based on a very outdated version of Dolphin):
https://forums.dolphin-emu.org/Thread-the-last-story-speedhack
which might be integrated now in this build(it was at one point):
https://forums.dolphin-emu.org/Thread-unofficial-ishiiruka-dolphin-custom-version
(no idea if it's enabled by default though)
The speedhack allows you to use efb2tex instead of efb2ram for the game, which is up to a 100% performance increase, depending how badly your GPU handles the game. Now the important part: With this increase, the game might be playable on an intel CPU(Haswell+) or Ryzen CPU at 4Ghz, anything lower is likely still not fast enough.
Keep the forum rules in mind please, all further discussion about those 2 builds has to happen in those threads and not in this thread here.