CPUs

Sep. 23rd, 2013 12:06 am
vesicular: (axbx)
[personal profile] vesicular
This winter I'm going to be doing a massive update to my arcade cabinet, which next month turns 10 years old (crazy when I think about it). I worked a bit this weekend on parting out some of the hardware, and tonight I worked on CPU's for the new rig I'm going to build.

CPU's are interesting because min/maxing them really depends on the task. The newest Intel chips came out a couple months ago (aka Haswell) and didn't go over so well for gamers. Haswell wasn't a very large jump for games over Ivy Bridge (the previous gen Intel chip) because Haswell is mostly a power consumption upgrade and thus it doesn't overclock as well as Ivy Bridge.

At first I thought, well, less power is nice, but I'm building this for a MAME cab so I need POWAH! Ivy Bridge is cheaper so I figured since the results are similar and the OC potential of Ivy is better I'd just go Ivy Bridge.

But not so fast. What I should have done is not read about _game_ use, but _emulation_ use. Different things! See, one thing Haswell adds is faster single core speed. This actually takes more power but the increase is fairly large. Given most emu's run single core, this greatly benefits emulation. So much so that the increase between Ivy Bridge to Haswell is about 20% for emu's. Much more than the flatline that normal gamers would see with the same setup.

And that makes it very worth it for me. Research time well spent.

Date: 2013-09-23 02:22 pm (UTC)
From: [identity profile] symbioid.livejournal.com
Wow. I would've gone for the lower power consumption as it is, because why not save money on electricity costs? I was shocked at how much Ivy Bridge chips still are.

Date: 2013-09-23 03:42 pm (UTC)
From: [identity profile] vesicular.livejournal.com
The actual electricity cost difference is pretty minimal. The lower power consumption is for laptops/mobile. And the weird thing is that Haswell at full load actually takes more power than IB, it's just that IB idles far higher. Since most people use their computers to surf the web and are idle a lot of the time, you get lower aggregate power consumption.

This is why the IB chips are still expensive. They're better for desktops because you can overclock them higher. Haswell also throttles at a lower temp. IB will happily sit at 90c but Haswell if it hits that temp will throttle a few hundred Mhz to save power.

Date: 2013-09-23 02:30 pm (UTC)
From: [identity profile] symbioid.livejournal.com
Or maybe it was the i7 that was more expensive than I expected (i have an i5).

I was looking into it, because I would like to do a really nice emu of PS2/GC and Wii (seeing that Dolphin 4 is out) and everyone was saying that it's more on the CPU than the GPU, so ... funny that you mention it. Helpful to know that about the cores as well, though I imagine that's more for MAME, and higher end systems use multi-core?

Date: 2013-09-23 03:45 pm (UTC)
From: [identity profile] vesicular.livejournal.com
Has nothing to do with the system emulated and everything to do with how emulation works. Very little can be passed off to multiple cores, because you're building a timing system, things have to happen in certain order so that the emulation is accurate. Mame has started to move certain things into a 2nd core, but it's mainly video and things that do not actually affect the emulation of the hardware. This is why very fast single core speeds are what is best for emulators.

Date: 2013-09-23 03:51 pm (UTC)
From: [identity profile] vesicular.livejournal.com
But yes, all emus are CPU bound, not GPU bound. The fastest GPU for my arcade monitor has an ATI chipset in it from 2006. It runs Street Fighter IV at 60fps. But you need a modern CPU OC'd to make that happen cuz all the major processing goes through that, not the GPU.