There are three things that a successful DIce pot needs, to some extent or another.
1) Surface to surface contact with dry ice.
2) Mass, to resist temperature changes.
3) Tight mounting to the CPU.
#1 Dry ice does not like to touch solid surfaces that are warmer than the DIce, at all. When it does it generates a gas layer that insulates it. This is what the acetone is for. It has nearly perfect contact with the dry ice as well as nearly perfect contact with the pot. #1 really comes down to the ability to hold acetone inside the pot in sufficient volume to touch a lot of DIce and a lot of pot surface area. CPU heatsinks are terrible for this.
#2 is fairly simple, a sudden change in CPU load can be soaked up to an extent by the mass of the pot. This is crucial if the pot lacks internal surface area. With enough mass you can spend 5m pulling the temps down and then the pot mass can sustain a load for a bit, even though there isn't enough surface area to hold the temp down. Think of it as a reservoir of cold. CPU heatsinks are terrible for this, too.
#3 is fairly obvious, if you aren't touching the CPU you aren't transfering cold. To actually touch the CPU in a meaningful way you need very tight mounting. Plastic frame heatsinks need not apply, you have to take the mounts off to attempt to use them as a CPU cooler. Metal mount CPU heatsinks are pretty good this way.
As an example, if you compare an F1EE and a Koolance V2 on Dry Ice on a low heat processor, say a core2duo, they're nearly identical. Both have plenty of surface area to keep the pot cold.
If you compare them on a 980x however, the koolance warms up a bit (fairly quickly) under load and then stays there at that temperature, as long as you keep it fed with dry ice. The F1EE does the same thing, but warms up a lot more, as it needs a larger temperature delta between the acetone and the pot to transfer enough heat due to the lower surface area.
For short benches, like WP32 (mighty short on a 980x) the F1EE can actually be better, that heatload for 3 seconds can't heat 5lbs of copper up nearly as much as it can heat the 2lbs of the Koolance (weights are estimates). Over the longer haul the F1EE warms up more than the Koolance, hence the WP1024 result.
A CPU heatsink will work to an extent on a low heat processor, and I mean really low heat. It won't get to full DIce temps due to a lack of contact.
As far as alcohol goes, you won't get as cold with it. The details of that are lounge material.
