From what I can tell from benchmarks I find online, the two CPUs in question are fairly close performance-wise in general purpose benchmarks. Which means that the Intel chip should spank the AMD chip when running emulators. The other thing that skews the benchmarks is when they include graphic performance in the benchmarks. AMD graphics are generally better than the Intel graphics.
The only drawback I can see is that the Core i3 doesn't have an unlocked multiplier, which means that overclocking is difficult if that's something you plan to do.
Intel Core i3-3225
22 nm Ivy Bridge 55W
3MB L3 Cache
Intel HD Graphics 4000
AMD A10-5800K APU
3.8GHz (4.2GHz Turbo)
32 nm Trinity 100W
4MB L2 Cache
AMD Radeon HD 7660D
If you plan on overclocking, you might want to look at this Core i5 processor...
Intel Core i5-2500K Sandy Bridge 3.3GHz (3.7GHz Turbo Boost) LGA 1155 95W Quad-Core Desktop Processor Intel HD Graphics 3000 BX80623I52500K
...and pair it with a good Z77 motherboard...
ASUS P8Z77-M LGA 1155 Intel Z77 HDMI SATA 6Gb/s USB 3.0 Micro ATX Intel Motherboard
GroovyMAME support forum on BYOAC