In the physical universe, computing power is limited by the Bakenstien bound and other physical limits. Although the computers available to a T3 society allow for simulations incredibly more complex than a human mind could comprehend, they are insufficient to preform any meaningful study into the nature of the slipstream itself. The slipstream simply has a much higher information density than the observable universe.
In an attempt to understand the slipstream, early T4 societies will build computers that push the limits of physical computation. While the supercomputers of more primitive societies tend to be built as large as possible with hundreds or thousands of cores working in parallel, these computers are built for efficiency by minimizing redundancy and maximizing density. Sidestepping the inherent inefficiencies of parallelization and cutting down on light lag, they are roughly 1 kg in mass and occupy a 1 liter spherical volume, comparable in size if not shape to a T0 laptop computer.
These computers are single use devices which preform all their computation at once and annihilating themselves in the process. The program is loaded as a slug of matter and antimatter which is compressed into a black hole. The black hole persists for 10−19 seconds before evaporating from Hawking radiation. During this time, the computer preforms about 1032 operations on a single petabyte of data. Ironically, although the clock speed surpasses the combined computing power of all conventional computers ever built the history of the cluster, it’s memory is comparable to a T0 supercomputer. A sad consequence of the speed of light, is that storage must be traded off for speed. Regardless, a Petabyte is more than all the information recorded by all societies below T0 in the history of the cluster.
The computer outputs it’s data all at once as it self destructs. It’s 1kg of matter turned completely into energy. About 90 petajoule or roughly the equivalent of 21 megatons of conventional explosive. This energy is released mostly in the form of Gama rays, and contains encoded in it a petabyte of information representing the computer’s final state. This information possibly containing astounding insights into the nature of reality. A T3 gamma ray observatory is sufficient to record this data, but additional computation by less violent computers is often necessary to make any sense of it.
Many lower tech civilizations on the other hand are satisfied simply with the ability to create a 21 megaton explosion at will. The means to coax one of these things to detonate is within the reach of any T-1 civilization determined enough to remove the safety plug and aim enough x-rays at the detector which serves as it’s on switch. The result is the near immediate conversion of 1kg of matter into pure energy.
The society that created these computers built them by the thousands with the goal of figuring out how to create habitable pocket universes within the slipstream or create slipknot connections to new solar systems. It is unknown what prevented this project from being completed, but it appears that their society collapsed before most of them could be used. Some of these devices were activated within population centers but these may have happened after the collapse, triggered accidentally by the S.T.A.L.K.E.R.s who tend to explore post collapse ruins in search of high tech artifacts to sell.
Although some civilizations have attempted to continue the research using these devices, other’s view them as nothing more than convenient weapons. Properly rigged They are much cheaper, lighter and require less maintenance than a conventional Nuclear weapon at least until the introduction of pure fusion warheads at T2. Many of these devices ended up on the black market, and lacking any radioactive material to trace, continue to confound regulatory bodies. Many backwater T-1 planets use them as their primary nuclear arsenal, and some lower tech academic institutions keep them with minimal security, either in storage or on display.
Although general consensus is that a detonation taking place without a high enough resolution Gamma ray observatory in the same solar system will result in the information being lost forever, some speculate that the device may somehow be capable of comprehending it’s environment and attempt to etch it’s output in nearby crystalline structures. Glass from detonation craters are almost as valuable as the devices themselves to some collectors.
Others theorize that the devices might even be capable of altering the genetic code of any humans exposed to the radiation without being killed. While most survivors simply suffer the usual radiation sickness, rumors persist of superhuman powers or messianic offspring. Several doomsday cults have gotten the idea that anybody killed in the blast is actually transported to a higher plane of existence, their mind being uploaded by the device as the body is annihilated. There is no documented evidence of this claim, but this hasn’t stopped some groups from trying to literally blow themselves to Kingdom Come.
As for why so many of them were left behind. Some believe that they vastly over-estimated the amount of detonations required to get a useful answer. They were either able to transcend early or simply intended the remaining devices to be used by less advanced civilizations who wish to uncover the secrets for themselves. Others insist it must be an elaborate prank, and that the devices simply produce a petabyte of convincing gibberish. That much computing power could construct fallacious proofs flawed just subtly enough that no mortal mind, man or machine, could ever hope to check them properly.
After all, How could a race so advanced be so careless as to leave 2 giggatons of nuclear weapons labeled as “Computational devices” just laying around for anybody to find?
A T-1 government is acquiring these devices to bootstrap their nuclear arsenal. They will pay good money to anybody who could help them acquire large numbers of them.
An underfunded offworld scientist is willing to work a corrupt regime in exchange for the rights to analyze the blast craters of their nuclear tests.
A T3 space navy is seeking to develop a next gen weapons system based on the same principle, Rather than calculating the secrets of the universe, it instead preforms a single brute force hacking attack. Such a weapon would be represented with the “Attacks an additional track” stunt.
A cult has acquired a device and seeks to detonate it in a populated city. It’s up to the PCs to stop them as the clock counts down.
A university on a low tech world is believed to posses one of these devices. The PCs are hired by a rival institution to steal and detonate it in deep space in a system with a working Gamma ray observatory in order to prevent it from falling into the wrong hands.
This idea is based on the Ultimate Laptop thought experement by Seth Loyd of MIT It is, as far as current science will allow, the fastest computer possible in the physical universe.