preacherwoman

I think the circuit you mentioned is incorporated into the interposer board we're using: https://github.com/N64-Freak/Xbox-CPU-interposer

Interesting, thanks for passing that along. Decent boost. Wonder if there's anything that can be done to increase RAM stability at higher clocks... Something like this or this might work. The interposer board is 50mm x 60mm if that helps. Balling the CPU-side of the interposer should be easy since the CPU aligns with the edges of the board, meaning the first one I linked should work fine. However, the other side will be more challenging since its offset a bit. You might have to get creative and use metal clips of some sort. Whatever fits and can handle getting hot without deforming too much. Some of the required components listed here are obsolete / no longer manufactured, or out of stock with insane manufacturing delays for new shipments. Specifically NC7SZ32M5X, NC7WZ07P6X, and SG-3030JC 32.7680KB0: ROHS are the hard ones to find. It looks like these are available on eBay at massively inflated costs if you want to go that route.

As someone who just received a few of his boards and is just getting into BGA rework, I understand where you're coming from. Before I start rambling, you should watch a few videos like this: That will give you a good overview of what you're in for when starting a mod like this. Keep in mind the mod will actually be a little more complicated than this, since you need to desolder the old CPU, solder down the interposer, and then solder down the new CPU. And then do all the surface mount components... Anyway I'll try to answer some of your questions: What is the best way to "ball" the underside of the interposer? See video, but basically you'll need a stencil that matches (ish) the bottom of the interposer, and one that matches the CPU. Something like this should cover your bases. That particular kit is probably overkill, but there's bound to be one close enough in that pile. You could probably find a more appropriate pack and save some money. When preparing to solder the CPU to the interposer, Lukas' github instructions say to "flux" every pad individually, but I think he means "tin" them? See video, but TL;DR you should flux before you tin to keep solder balling predictably and sticking to pads and not other solder. What is the best way to align the interposer to the board? Basically by eye, usually you use the silkscreen outline on the motherboard to align the corners. I haven't gotten this far yet, but I would guess you align the corner closest to the CPU pads on the motherboard side and get it looking as reasonable as you can before you reheat the CPU to solder it down. How do I hook up a #STPCLK switch to the VCC/GND leads? If I'm understanding correctly, to cut CPU performance in half you connect the VCC/GND pins as described on the Github page. So, you should just need a switch to break the connection of the VCC line to allow you to toggle between 100/50% mode. Lukas has already recommended a good rework station that I will pick up in 3-4 weeks or so, but does anybody have recommendations for a soldering iron/station? Maybe some sort of kit that comes with everything I will need for this project? In fact, what WILL I need for this project? I have a basic Weller setup like this, but the sky is the limit here and just depends on what you're comfortable with. A rough list for this project would be something like: Reasonable soldering iron setup Hot air or BGA rework station Solder and flux paste Isopropyl alcohol Good pair of very narrow tweezers for picking/placing SMD components and manual BGA ball alignment Roll of desoldering wick .76mm solder balls Appropriate BGA stencils that match the interposer and CPU All of the SMD components listed on his Github page (this has been the killer for me) Compatible CPU Maybe optional: magnifying setup of some variety, depends on how good your eyes are... I'm not aware of a kit for something like this, but let me know if you find one. Could I theoretically use XBoverclock to push this CPU even higher? Maybe to 1.6Ghz? I haven't done a lot of research into this, but maybe. Cooling is one thing, but without the ability to easily tweak voltages its going to be tough to keep the system stable. Also some quick reading seems to indicate changing the FSB speed quickly destabilizes the system. You might want to open up a separate thread for this specifically just to see how far people have gone with XBoverclock. I'm also curious... Anyway, hope that helps! Curious to see how you get on, and I'll let you know how it goes for me. The lead times on some of the SMD components are insane, so I'm not sure when I'll manage to finish this honestly...