specs:
I5 3500k
HD 7870 AMD
Well I try using an emulator in Eclipse but it's pretty sluggish even with my i5 3500k. I found out that it only uses one core. So what I did is check the box that said "use Host GPU" to hopefully uses the horse power of my GPU. But when I check MSI burner, my GPU usage is 0%. And one of my CPU cores still uses over 95%. It also has the same performance. How come it's not utilizing my GPU after checking the used Host GPU.
With i5 3500K you can only use ARM based emulator instead of Intel's x86 emulator, which is 10~20 times faster (I think i5 misses these CPU extensions: EM64T, Execute Disable (XD) Bit), see here for x86 emulator support requirement.
For solve your speed issue, I would strongly recommend using Genymotion, it provides fast x86 emulators with Eclipse integration, and I have not encounter any issue with it for the time I've been using it.