@donluca: not saying you give people false hopes but 5GHz is like around the absolute top the G3258 could reach on a select number of mobos in ideal conditions.
I easily reached 5.2Ghz on single core my G3258 but it crashed on some occasion, so since there were no gains from 5 to 5.2, I decided to roll it back to a more relaxed 5Ghz. And I didn't even need to boost the voltages. Actually I managed to slightly lower the voltages on mine once I got it back to 5Ghz to run it cooler.
If I wanted to use both cores, I had to stay at 4.8Ghz, but there was no point since I only used it for GroovyMAME.
I used an Asrock Motherboard I paid 35€, so nothing astronomical.
Variance do exists, I've read of people having difficulties going beyond 4.2Ghz, so definitely keep that in mind, although most people happily reached 4.8Ghz without issues.
This is absolutely not true. Optimization is always a concern.
This is absolutely and completely false. I (and many others) have reached several times to MAME devs asking for optimization on some drivers and they clearly told us that optimization is on the rock bottom of the list.
People always think of MAME as a way to play arcade games on their PCs. This is not the case. MAME is a preservation project aimed at discovering how this old hardware worked, documenting it in the most complete and in-depth way possible (just look at the source files, you'll be amazed at the amount of information you'll find). Games run because, of course, once documented you know how boards work and you're able to reproduce their behavior. MAME is a godsend to arcade operators and people who repair PCBs because thanks to the sheer amount of information in it they're able to troubleshoot and repair those old boards.
As such, optimization is never been an issue, because getting people to run the games on their devices has never been a priority, just a consequence.
It's only in recent times that some gentle soul decided to take a look at some of the drivers and do some optimization on them, but that's never been a priority.
This is also untrue. There are several drivers in MAME that take advantage of multiple cores. I ran some benchmarks a while back and these games (there are others) were 15-27% faster on a quad-core CPU vs a dual core CPU...
blitz
gauntleg
gradius4
pinkswts
propcycl
slrasslt
We are talking GroovyMAME here, and I'm pretty sure GM doesn't use multithreading on anything.
And, besides, MT on MAME is pretty broken. So yeah, it might speed up the emulation, but it will bring other issues along.
And Pink Sweets doesn't use it. Just the more modern and demanding 3D games.
But, again, we're talking GM here, and I'm pretty sure GM doesn't use MT at all.
This is not completely true either. On old cards, you may run into issues with low texture memory at higher resolutions. You also can't run any HLSL effects on really old video cards.
Again, we're talking GM which is mainly aimed at CRT users. But I'll give you that: There are people which are using GM on LCDs to take advantage of frame_delay, so that's partially true, although any modern low end graphic card will do the job.
This is only true on drivers that don't utilize multiple cores. And I wouldn't say "smashes". The performance can be comparable and when you consider the price difference, it's a total bargain. Here's a thread with some benchmarks I did a while back comparing a G3258 to the i7-4790K both at 4.5GHz...
https://www.mameworld.info/ubbthreads/showflat.php?Number=371718
Drivers that use multiple cores can be counted on one hand's fingers and, as said before, the MT implementation brings issues with it.
I said "smash" because even getting the same results, it's a 50€ vs a much more expensive processor.
EDIT: I'd also like to add that you could OC the G3258 without needing a third party cooler, which is a nice added bonus. Not sure you could reach those frequencies with your i7 with the stock cooler. I'd be really impressed if that was the case.