A CPU that runs entirely on GPU • Hacker News Board

Re: A CPU that runs entirely on GPU

#101

Post by zackmorris » Wed, Mar 04, 2026, 5:04 PM UTC

bastawhiz wrote: post #7

lorenzohess wrote: post #3

Out of curiosity, how much slower is this than an actual CPU?

Based on addition and subtraction, 625000x slower or so than a 2.5ghz cpu

I wish the project said how many CPUs could be run simultaneously on one GPU.

It might be worth having a CPU that's 100 times slower (25 MHz) if 1000 of them could be run simultaneously to potentially reach a 10 times speedup for embarrassingly parallel computation. But starting from a hole that's 625000x slower seems unlikely to lead to practical applications. Still a cool project though!

Re: A CPU that runs entirely on GPU

#102

Post by yjftsjthsd-h » Wed, Mar 04, 2026, 5:16 PM UTC

user____name wrote: post #58

Someone needs to implement LLVMPipe to target this isa, then one can run software OpenGL emulation and call it "hardware accelerated".

Surely that would be hardware decelerated

Re: A CPU that runs entirely on GPU

#103

Post by yjftsjthsd-h » Wed, Mar 04, 2026, 5:18 PM UTC

robertcprice1 wrote: post #67

Hey everyone thank you taking a look at my project. This was purely just a “can I do it” type deal, but ultimately my goal is to make a running OS purely on GPU, or one composed of learned systems.

This is hilarious and profoundly in the spirit of hacker news. Thanks for posting:)

Re: A CPU that runs entirely on GPU

#104

Post by downrightmike » Wed, Mar 04, 2026, 5:28 PM UTC

bob1029 wrote: post #28

A fun experiment but I wonder how many out there seriously think we could ever completely rid ourselves of the CPU. It seems to be a rising sentiment. The cost of communicating information through space is dealt with in fundamentally different ways here. On the CPU it is addressed directly. The actual latency is minimized as much as possible, usually by predicting the future in various ways and keeping the spatial ex…

Mainframes still exist, so CPU isnt going anywhere. Too useful of a tool

Re: A CPU that runs entirely on GPU

#105

Post by mghackerlady » Wed, Mar 04, 2026, 5:31 PM UTC

robertcprice1 wrote: post #67

Hey everyone thank you taking a look at my project. This was purely just a “can I do it” type deal, but ultimately my goal is to make a running OS purely on GPU, or one composed of learned systems.

GNU/GPU

Re: A CPU that runs entirely on GPU

#106

Post by mghackerlady » Wed, Mar 04, 2026, 5:34 PM UTC

volemo wrote: post #38

micw wrote: post #14

Earlier quoted context omitted.

Linux runs everywhere

Except on my stupid iPad “Pro”. :(

iirc theres an app on the app store that's basically a small alpine container

Re: A CPU that runs entirely on GPU

#107

Post by fc417fc802 » Wed, Mar 04, 2026, 5:48 PM UTC

chris_money202 wrote: post #53

fc417fc802 wrote: post #44

Earlier quoted context omitted.

> I wonder how many out there seriously think we could ever completely rid ourselves of the CPU. How do you class systems like the PS5 that have an APU plugged into GDDR instead of regular RAM? The primary remaining issue is the limited memory capacity. I wonder if we might see a system with GPU class HBM on the package in lieu of VRAM coupled with regular RAM on the board for the CPU portion?

I don’t think the remaining issue is memory capacity. CPUs are designed to handle nonlinear memory access and that is how all modern software targeting a CPU is written. GPUs are designed for linear memory access. These are fundamentally different access patterns the optimal solution is to have 2 distinct processing units

GDDR has high bandwidth but limited capacity. Regular RAM is the opposite, leaving typical APUs memory bandwidth starved.

Both types of processor perform much better with linear access. Even for data in the CPU cache you get a noticable speedup.

The primary difference is that GPUs want large contiguous blocks of "threads" to do the same thing (because in reality they aren't actually independent threads).

Re: A CPU that runs entirely on GPU

#108

Post by _blk » Wed, Mar 04, 2026, 6:04 PM UTC

"Result: 100% accuracy on integer arithmetic" - Could someone with low-level LLM expertise comment on that: Is that future-proof, or does it have to be re-asserted with every rebuild of the neural building blocks? Can it be proven to remain correct? I assume there's a low-temperature setting that keeps it from getting too creative.

The creative thinking behind this project is truly mind boggling.

Re: A CPU that runs entirely on GPU

#109

Post by jhuber6 » Wed, Mar 04, 2026, 6:06 PM UTC

low_tech_punk wrote: post #86

Saw the DOOM raycast demo at bottom of page. Can't wait for someone to build a DOOM that runs entirely on GPU!

Depends entirely on your definition of 'entirely', but https://github.com/jhuber6/doomgeneric is pretty much a direct compilation of the DOOM C source for GPU compute. The CPU is necessary to read keyboard input and present frame data to the screen, but all the logic runs on the GPU.

Re: A CPU that runs entirely on GPU

#110

Post by mihaitodor » Wed, Mar 04, 2026, 6:23 PM UTC

nine_k wrote: post #56

DonThomasitos wrote: post #52

I don‘t understand why you would train a NN for an operation like sqrt that the GPU supports in silicon.

I see it as a practical joke or a fun hack, like CPUs implemented in the Game of Life, or in Minecraft.

It’s been done already. Have a look at Quest for Tetris: https://codegolf.stackexchange.com/questions/11880/build-a-w...